The present invention relates to a device for de-activating the boost pressure compensation device when it is not required.
Background of the Invention
A limp-home device is an arrangement, which ensures lower power than a fully rated declared power of an engine to negotiate with the maximum gross vehicle weight conditions.
Vehicles such as cement and ore carriers and the like run on full power only during one way of operation of the vehicle. In the return trip, they rectum empty and in such a condition there is no need to provide the full rated power of the vehicle. By cutting off the boost pressure, the fuel injection equipment is made to deliver less fuel to the engine and thereby runs on lower power than the rated full power. The lower power thus obtained is found adequate for pulling the vehicle for empty vehicle operation. By cutting off the boost pressure on and off valve, the limp home activity is achieved with less fuel consumption and thereby mileage improvement.
Summary of the Invention
The present invention relates to a boost pressure on-off valve that can be introduced on any turbocharged diesel engine to enable or disable the boost pressure actuation on the Manifold boost Pressure Compensation (MFC) unit fitted on the Fuel Injection Pump (FIP). The fuel injected for an engine is optimized with respect to the boost pressure at the air intake manifold.
The engines are optimized for standard sea level conditions with a specific air inlet temperature and humidity values specified in engine test standards. For different

site barometric pressures, the fuel delivery is altered corresponding to the manifold boost pressures using a manifold boost pressure compensator fitted on the FIP of the turbocharged diesel engines.
The device according to the invention, when introduced between the MFC and the intake manifold, results in the fuel delivery with or without the boost pressure application by manipulation of this valve. This valve can either be an electric or mechanical valve, which can be switched on or off. In case of electric valve, the control can be provided on the dashboard of the driver's cabin for switching the valve on or off by the driver himself while seated in his seat.
The invention has an advantage of using the engine in two power modes with and without boost pressure compensation. This feature can be made use of with MFC on, when the vehicle is fully loaded one way and with MFC off on return in unlade condition. By this invention, the engine is allowed to operate in normal rated and de-rated power condition and thereby resulting in significant fuel savings for the vehicle operators.
Accordingly, the invention provides a mechanism for enabling/disabling the boost pressure in a turbocharged engine comprising an inlet manifold situated in a cylinder head, a fuel injection pump, a manifold boost pressure compensator positioned atop the fuel injection pump, said fuel injection pump and the manifold boost pressure compensator being situated in a cylinder block, characterized in that said mechanism comprises: means to enable or disable the air pressure from the intake manifold into the manifold boost pressure compensator depending on the load carried by the vehicle, the means being activated to disable the air pressure food the intake manifold into the manifold boost pressure compensator when the vehicle is moving on low or empty load thereby improving fuel efficiency and the means being de-activated to enable the air pressure from the intake manifold into

the manifold boost pressure compensator when the vehicle is moving on foil load milder normal operation conditions.
Brief Descriptions of the Drawings
Fig 1 is the prior art in-line FIP without the boost pressure on-off valve.
Fig 2 shows the schematic of a manifold pressure compensator
Fig 3 shows the schematic of the present invention with the boost pressure on-off valve, wherein the valve is in a switched OFF condition on an in-line FIP,
Fig 4 shows the schematic of the present invention with the boost pressure valve is in an ON condition on an in-line FIP,
Fig 5 shows the prior art rotary FIP without the boost-pressure on-off valve,
Fig 6 shows the schematic of the present invention with the boost pressure on-off valve, wherein the valve is in a switched OFF condition on a rotary FIP,
Fig 7 shows the schematic of the present invention with the boost pressure valve is in an ON condition on a rotary FIP,
Fig 8 shows the engine performance comparison with and without the boost pressure on-off valve.
Detailed Description of the Invention
Figures 1 and 5 are a schematic diagram of an in-line engine and a rotary engine respectively. Here, the air pressure acts from the inlet manifold (3) to the Manifold

boost Pressure Compensation (4) on the in-line FIP directly in regular operation. The schematic shows a rocker cover (1) situated above the cylinder head (2). Air pressure from the intake manifold flows into the intake of the MPC (4), which is situated on the top surface of the in-line fuel injection pump by means of a hose pipe. Thus at any load condition, the vehicle will continue to run in its rated power. The MPC (4) is preferably connected with a nylon hose with banjo end to the intake manifold.
The MPC (4) is illustrated in Figure 2. Basically, the MPC (4) is an add on device to the fuel injection pump fitted on turbo charged diesel engines. The MPC (4) consists of a boost pressure air connection tapping (A), which receives the boost pressure I’m air inlet manifold of the engine and such pressure deflects the diaphragm (D). The diaphragm (D) is connected to the fuel injection pump rod connecting to control the rack (R) of the fuel injection pump, which increases or decreases the fuel delivery. To assume normal position of the diaphragm (D) on release of pressure, a diaphragm rectum spring (S) is also provided in the MPC (4).
The invention will now be described with reference to figures 3 and 4. It should be noted that the inventive concept remains the same for the invention illustrated in figures 6 and 7 except for the fact that the engine is of rotary type in the latter set of figures.
As it can be seen in figures 3 and 4, the boost pressure on-off valve (10) is positioned on the engine such that it is connectable to the inlet manifold (13) and the MPC (14) respectively at each of its ends. Figure 3 shows the valve (10) in the OFF condition, referring to the full load operation of the vehicle, thereby running in its full rated power. The boost pressure food the inlet manifold (13) enters into the MPC (14) through the valve (10). In this condition, the air from the exhaust port with silencer open to the ambient is cut off. For a given pressure on the accelerator

pedal by the driver of the vehicle, the power, and consequently, the fuel consumption vary.
As shown in figure 4, when the vehicle is running on empty load the boost pressure valve (10) is switched ON, in which condition, the entry of the air pressure food the inlet manifold (23) into the valve (10) is cut off, thereby reducing the power of the engine and cutting off fuel supply by the FIP. The air pressure from the exhaust port with silencer open to ambient is allowed to pass to the FIP through the MFC (24). Thus by a simple operation of a valve the engine can be used in two power modes with and without boost pressure.
As already explained earlier, the MFC (4, 14, 24) has a diaphragm exposed to the boost air pressure and a rod connects diaphragm and the fuel pimply rack which can alter the rack position corresponding to the deflection of the diaphragm due to the air pressure applied. The actuation of the diaphragm against a particular pressure and the required movement is determined by the diaphragm, return spring and the physical movement of the rod. The MFC has a connecting port for boost pressure connection from the intake manifold. The movement of the diaphragm and connecting stem provides additional fuel pump rack movement, which alters the normal fuel delivery without the boost pressure compensation. That is, if the air pressure is not applied, the rack movement is only a mechanical movement effected by the pump lever connected to the accelerator pedal of the vehicle.
In the aforesaid conditions, there will be two different fuel deliveries and corresponding power output with and without the boost pressure applied to MFC for the same accelerator lever position.
The boost pressure on-off valve (10) can preferably be a solenoid valve but not limited to that. The valve could be a mechanical, electrical, pneumatic or hydraulic valve or a combination of the functions of two or more of such valves.

The valve (10) is mounted on the engine by means of supporting brackets (not shown). A hose is connected to the MPC on the fuel injection pump and the other end of the hose is connected to outlet of the valve (10). Another hose is fitted on the intake manifold for boost pressure sensing and the other end is connected to the inlet of the valve (10). An isolator switch (not shown) for electrical power is mounted on the dashboard in the driver's cabin for activating/de-activating the boost pressure on-off valve.
The performance graphs of a typical engine with boost pressure on-off conditions are illustrated in Figure 8, which are self-explanatory. The results of the tests carried out on an engine with a rated power of 132 kW (H series - 6DTI) incorporating the valve can be seen in table I and table II as shown below.



Obvious alterations and modifications knowing to persons skilled in the art are not excluded from the scope and ambit of the appended claims.

WE CLAIM:
1. A mechanism for enabling/disabling the boost pressure in a turbocharged engine comprising an inlet manifold situated in a cylinder head, a fuel injection pump, a manifold boost pressure compensator positioned atop the fuel injection pump, said fuel injection pump and the manifold boost pressure compensator being situated in a cylinder block, characterized in that said mechanism comprises: means (10) to enable or disable the air pressure from the intake manifold into the manifold boost pressure compensator depending on the load carried by the vehicle, the means (10) being activated to disable the air pressure from the intake manifold into the manifold boost pressure compensator when the vehicle is moving on low or empty load thereby improving fuel efficiency and the means (10) being deactivated to enable the air pressure foot the intake manifold into the manifold boost pressure compensator when the vehicle is moving on full load under normal operation conditions.
2. The mechanism as claimed in claim 1, wherein the said means (10) is a valve.
3. The mechanism as claimed in claim 2, wherein the valve is a solenoid valve.
4. The mechanism as claimed in claim 3, wherein the valve is either a mechanical or electrical or hydraulic or pneumatic valve.
5. The mechanism as claimed in claim 1 to 3, wherein the inlet manifold, the manifold pressure compensator and the valve are interconnected by means of hosepipes, which are preferably made of nylon.
6. The mechanism as claimed in claim 1, wherein the manifold pressure compensator has a diaphragm exposed to the boost air pressure and a rod is

provided to connect diaphragm and a field pump rack which can alter the rack position corresponding to the deflection of the diaphragm due to the air pressure applied.
7. The mechanism as claimed in any one of the preceding claims, wherein the valve is operated by means of an isolator switch fitted on the dashboard of the driver's cabin in the vehicle for ease of switching from one mode to the other by the driver.
8. A mechanism for enabling/disabling the boost pressure in a turbocharged engine as described hereinbefore with reference to figures 2-4 and 6-8.