Field of invention

The present invention is related to an Integrated Engine Camshaft for the actuation of unit Fuel Injection Pump by a Trilobe (Figure 2) design. The Trilobe is integrated in a single Camshaft alongside intake and Exhaust Cam Lobes to actuate intake & exhaust valves respectively.

Background of invention

In Modern diesel Engines, a fuel injector injects fuel at high pressure directly inside the combustion chamber. Prior to Injection, the fuel is pumped by either by an inline pump or distributor pump. The inline & distributor pumps are actuated by separate Cam lobes. There is no direct connection between fuel injection Cam lobes and intake, Exhaust Cam lobes, where as in this invention Fuel injection cam lobe (trilobe) and Intake & Exhaust Cam lobes are integrated in a single cam shaft. So, the fuel injection pump directly actuated by the cam shaft's trilobe, thus the additional parts required to actuate the fuel injection pump are eliminated by this invention.

Objects of invention

The main object of the present invention is to provide a trilobe integral with the camshaft for actuating fuel injection pump.
Yet another object of the present invention is to provide improved packaging of the fuel pump by directly actuating it by camshaft.

Brief description of drawings

According to the present invention,

Figure 1 shows a Trilobe camshaft with assembly details.

Figure 2 shows Cam shaft & Trilobe

Figure 3 shows Unit Fuel Injection Pump Details.

Figure 4 shows details of a Trilobe cam.

Brief description of invention

The invention relates to an actuator (Trilobe) design for cam shaft which drives the unit fuel injection pump. An integrated engine camshaft for the actuation of both Intake and Exhaust systems which is integrated with an multilobe (Trilobe) (2) specially designed for actuating cam driven unit Fuel injection pump for pumping the fuel in the common rail system. This camshaft comprises of both intake and exhaust system's cams in a single camshaft for the actuation of intake & exhaust valves respectively.

The Unit fuel injection pump (3) feeds fuel to the common rail at a higher pressure in the order of maximum of 1450 bar. Delivery maximum pressure from the fuel injection pump depends on the maximum stiffness of the compression spring inside the fuel injection pump. Any maximum pressure can be delivered from the fuel injection pump by the actuation of Cam shaft.. The rotary motion of the camshaft is converted into reciprocating motion of the fuel pump piston (12) by the Trilobe (2) directly. Cam angle (15) verses lift in trilobe (16) is designed based on the Fuel pressure & delivery requirement. Over a 360 cam angle, it attains three times peak lift. Any dimension of base circle radius and cam lift of trilobe (16) can be used. The common rail in turn feeds the fuel to the Fuel injector.

Detailed description of invention

The invention relates to an actuator (multilobe) design for cam driven unit injection pump. An integrated engine camshaft for the actuation of both Intake and Exhaust systems which is integrated with an Trilobe specially designed for actuating cam driven unit Fuel injection pump for pumping the fuel in the common rail system. This camshaft comprises of both intake and exhaust system's cams in a single camshaft for the actuation of intake & exhaust valves respectively.

The invention relates to an actuator (Trilobe) design for cam driven unit injection pump. The Unit fuel injection pump (3) feeds fuel to the common rail at a higher pressure in the order of maximum of 1450 bar. Delivery maximum pressure from the fuel injection pump depends on the maximum stiffness of the compression spring inside the fuel injection pump. Any maximum pressure can be delivered from the fuel injection pump by the actuation of Cam shaft.. Figure 1 shows the Pulley for the belt driven cam shaft (1), Exhaust Valve (4), intake valve (5), and figure 2 depicts the exhaust valve cam (6), intake valve cam (7). The rotary motion of the camshaft is converted into reciprocating motion of the fuel pump piston (12) by the Trilobe (2) directly. Cam angle (15) verses lift in trilobe (16) is designed based on the Fuel pressure & delivery requirement. Over a 360 cam angle, it attains three peak lifts. Any dimension of base circle radius and cam lift of trilobe (16) can be used. The common rail in turn feeds the fuel to the Fuel injector.

This overhead camshaft has got 6 cams with cam lobes with different Phase angles and it is integrated with trilobe as shown in the Figure 2.

This trilobe (2) can also be made of any profile with respect to the center of a lobe (Refer Figure 4).

Tappet Roller (14) of the Fuel injection pump (3) is made in contact with the trilobe (2) by a compression spring (13). Whenever trilobe (2) is in opening flank during rotation, tappet roller (14) is moved and the spring (13) gets compressed. The fuel already present in the fuel chamber gets compressed and reaches max pressure in the order of maximum of 1450 bar. Delivery maximum pressure from the fuel injection pump depends on the maximum stiffness of the compression spring inside the fuel injection pump. Any maximum pressure can be delivered from the fuel injection pump by the actuation of Cam shaft, when the trilobe (2) attains max lift. The high pressure fuel is then pumped to the common rail where the high pressure fuel is stored and it is injected to the combustion chamber by the fuel injectors. After delivery of fuel, vacuum is developed in the fuel chamber (11), so when the trilobe is in closing flank, suction takes place from the pump line to the fuel chamber (11). Thus the suction (9) and delivery (10) take place when the tappet is actuated by the trilobe (2) and is returned by the compression spring (13) (Refer Figure 3). So, the fuel is delivered to the common rail by the unit pump which is actuated by trilobe in the camshaft.

A Forged steel overhead camshaft is comprising of a Triiobe for actuating Fuel Pump and a pickup to trigger the cam sensor. The Triiobe is profile machined on a cylindrical Camshaft. The Triiobe Cam consists of three equidistant peaks along the circumference of the Shaft. The Fuel pump is assembled on holder, which is in turn assembled on the Cylinder head by studs. The fuel pump is placed at an angle to the camshaft. The Camshaft consists of three intake and three exhaust Cam lobes for direct actuation of the Valves. The Camshaft is driven by pulley connected to the front end of the camshaft. The camshaft is belt driven and is a direct overhead type using a mechanical Tappet. The Camshaft is supported by 4 Journal bearings. The Camshaft is additionally supported by Cylindrical Roller Bearing at the rear End to withstand the load offered by the fuel injection pump.

As the Fuel pump is directly actuated by camshaft, it improves the packaging of the fuel pump.

The Invention accounts for the elimination of rocker mechanism and its corresponding parts, thereby reducing the reciprocating mass. Since the Fuel pump (3) is directly actuated by camshaft, it improves the packaging of the fuel pump. Since the cams sensor pick up (8) is directly machined on the camshaft it provides a more accurate measurement, when compared with the Sprocket pickup.

The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim:

1. An Integrated Engine Camshaft for actuating Fuel Injection Pump comprising

at least one multilobe cam (2) integrated with an integrated engine camshaft;

a pickup (8) to trigger the cam sensor;

at least one provision for mounting the pulley for the belt driven system (1);

at least one exhaust valve cam lobe (6) and at least one intake valve cam lobe (7);

2. The camshaft as claimed in claim 1 wherein said multilobe cam consists of three equidistant peaks along the circumference of the Shaft to provide three times peak lift in one rotation of said camshaft.

3. The camshaft as claimed in claim 1 wherein said multilobe cam consists of equal number of peaks with number of lobes along the circumference of the Shaft to provide equal number of peak lift in one rotation of said camshaft.

4. The camshaft as claimed in claim 1 wherein said multilobe cam (2) is also provided in different profile with respect to the center of a lobe for varying the number of peak lift in one rotation of said camshaft based on the fuel pressure & delivery requirement.

5. The camshaft as claimed in claim 1 wherein said multilobe cam (2) is a trilobe cam integrated with an integrated engine camshaft is configured for actuating fuel injection pump for pumping the fuel in the common rail system at a higher pressure in the order of 1450 bar.

6. The camshaft as claimed in claim 1 wherein said camshaft multilobe design can deliver any order pressure of fuel injection pump which depends on stiffness of the compression spring inside the fuel pump.

7. The camshaft as claimed in claim 1 wherein said integrated engine camshaft comprises of both intake and exhaust system's cams in a single camshaft is configured for the actuation of intake & exhaust valves respectively.

8. The camshaft as claimed in claim 1 wherein the rotary motion of said trilobe cam (2) is directly converted into reciprocating motion of the fuel pump piston (12).

9. The camshaft as claimed in claim 1 wherein cam angle (15) and the cam lift (16) in said trilobe cam is provided based on the fuel pressure & delivery requirement.

10. The camshaft as claimed in claim 1 wherein base circle radius (17) and cam lift (16) of said trilobe cam (2) can be varied as per requirement.

11. The integrated engine camshaft for actuating fuel injection pump as substantially as herein described with reference to accompanying drawings.