FIELD OF INVENTION:

The invention relates to fuel supply arrangement for quicker start of an internal combustion engine.

BACKGROUND OF THE INVENTION:

There are different types of configurations for a fuel feed pump supplying fuel to an internal combustion engine.

In some of the Common Rail injection systems, mechanical feed pump is used for suction of fuel from tank to high pressure pump. In systems which use mechanical feed pumps, the amount of fuel delivered is dependent on engine speed. During start phase, the engine speed will be low, therefore fuel delivery by the mechanical feed pump may not be sufficient during the start phase. In such situations an additional electric feed pump is used to aid the mechanical feed pump during start phase.

The delivery from mechanical feed pump will have good startability during normal ambient temperature, but for the vehicles operating in cold regions where ambient temperatures is less than 0°C, the startability will be an issue. This is because, the voltage supplied by the battery during the cold temperatures is less. Less battery voltage results in lower RPM of the starter motor. Lower RPM of the starter motor results in lower RPM of the engine and lesser delivery of fuel from the mechanical pump which is directly driven by the engine.

For such situations, an electric feed pump can be used to supply fuel only during start phase of the engine.

In present systems where electrical feed pump is used during the starting phase of the engine, normally the ECU controls the operation of the electrical feed pump. The ECU, activates the feed pump by providing electric power to the feed pump during the starting phase of the engine and once the engine speed is enough to sustain fuel delivery by the mechanical pump, the ECU de-activates the electric feed pump by cutting off the power.

ADVANTAGES OF THE INVENTION:

The invention proposes a fuel supply arrangement which can be fitted in existing vehicles to improve the startability of the engine. Thus the invention can be used as a retrofit for existing vehicles.

The power supply arrangement is simple without needing any additional components. A simple wiring arrangement from the battery to an electrical pump is provided.

BRIEF DESCRIPTION OF THE DRAWINGS:

Figure 1: Shows the schematic of the fuel supply arrangement

DESCRIPTION OF THE INVENTION:

Shown in figure 1 is a schematic of the fuel supply arrangement according to the invention. The schematic shows an ignition switch 10, power supply lines 12 and 14, an electric feed pump 16 supplying fuel to a high pressure pump which is not shown. The electric feed pump 16 when provided with electric power, draws fuel from the tank 18 and supplies the fuel through the fuel supply path 22 to a high pressure pump which is not shown. A battery which is not shown in figure supplies electrical power to the fuel supply arrangement through the line 11. The power supply line 12 supplies power to a starter motor 20. A parallel power supply line 14 supplies power to the electric feed pump 16.

When the ignition switch 10 is closed to supply power to the starter motor 20, the parallel power supply line 14 connects the electrical feed pump 16 to the power supply.

The starter motor typically runs at an RPM of about 130 when the battery has sufficient charge to provide a required voltage. The voltage provided by the battery is dependent on the ambient temperature. If the ambient temperature is low, for example, about 0 degrees, the battery voltage comes down. When the battery voltage is low, the battery will not be able to provide enough power to the starter motor. The starter motor runs at a reduced RPM. As the starter motor drives the engine during the starting phase, the engine also runs at reduced RPM. During such situations, if the present invention was not present in the vehicle, the mechanical pump which is directly driven by the engine supplies lesser fuel to the engine. As the fuel supplied by the mechanical pump is not enough to combust, the starting of the engine is delayed. Also there may be misfires causing more emissions and consuming more fuel.

The invention proposes a fuel supply arrangement during starting phase of the engine. The electrical feed pump 16 is provided to supply fuel during the starting phase of the engine where engine RPM is low. The electrical feed pump 16 is provided power supply through the parallel power supply line 14. The electrical pump 16 receives electrical power when the ignition switch 10 is closed. During the same period the starter motor 20 too receives the power. The starter motor drives the engine when provided with electrical power. If the ambient temperature is low, the starter motor 20 runs at a lower speed, hence the engine which is not shown, also runs at lower speed. As the electrical feed pump 16 starts running at the same time when the starter motor starts 20 running, the electrical feed pump 16 starts drawing the fuel from the fuel tank 18 and delivers to the high pressure pump. This fuel supply will be in addition to a mechanical fuel pump which is driven directly by the engine. The mechanical pump which is driven by the engine also delivers the fuel to the high pressure pump. As both the pumps are delivering fuel to the engine, there is enough fuel available in the cylinders for combustion. Once the combustion starts, the engine RPM increases. At this time, the power to the starter motor 20 is disconnected through the switch. Disconnection of power to starter motor 20 also results in disconnection of power to the electric feed pump 16. The electric feed pump 16 stops. Because the combustion of the fuel is occurring in the cylinders, the RPM of the engine is enough to drive the mechanical pump to deliver required quantity of fuel to the engine.

Thus using an electrical feed pump during the starting phase of the engine helps in quicker start of the engine. Also as the electrical feed pump is connected only during the starting of the engine and later disconnected, there is not much load on the battery.

As the engine starts quickly, there are no misfirings. This saves the fuel and also reduces the emission.

WE CLAIM:

1. A fuel supply arrangement for an internal combustion engine, the said fuel supply arrangement comprising an electrical feed pump (16), a power supply line (14) providing electric power to the electrical feed pump (16), the said power supply line (14) being in parallel to the power supply line (12) providing electric power to a starter motor (20)

2. A fuel supply arrangement according to claim 1 wherein the electrical power to the electrical feed pump (16) is provided through an ignition switch (10)

3. A fuel supply arrangement according to claim 1 wherein providing electrical power to the starter motor (20) results in providing electrical power to the electric feed pump (16)

4. A fuel supply arrangement according to claim 1 wherein cutting off of the electrical power to the starter motor (20) results in cutting off of electrical power to the electric feed pump (16)