Gas fuel feed device
It is an object of this invention to provide a gas fuel supply system in which a controllable range in the fuel injection quantity control by an injector is enlarged. According to one preferable aspect of this invention, the gas fuel supply system comprises an injector provided in an intake pipe of an internal combustion engine, a fuel supply passage for supplying the gas fuel to the injector, and means for controlling pressure of the gas fuel supplied to the injector through the fuel supply passage by using negative pressure in the intake pipe such that the pressure of the gas fuel increases if the negative pressure in the intake pipe decreases, and the pressure of the gas fuel decreases if the negative pressure in the intake pipe increases.
1. A gas fuel supply system for supplying gas fuel to an internal combustion engine, comprising:
a fuel supply passage for supplying the gas fuel to an injector; and
source pressure control means for controlling pressure of the gas fuel supplied to the injector through the fuel supply passage by using negative pressure in an intake pipe such that the pressure of the gas fuel increases if the negative pressure in the intake pipe decreases, and the pressure of the gas fuel decreases if the negative pressure in the intake pipe increases;
wherein the source pressure control means comprises a diaphragm type regulator provided in the fuel supply passage, and a negative pressure supplying passage which connects a diaphragm chamber of the regulator to the intake pipe;
wherein a throttle valve is provided in the intake pipe for adjusting an amount of intake air, and the negative pressure supplying passage connects the diaphragm chamber of the regulator to a downstream side of the throttle valve in the intake pipe; and
wherein the regulator is a two-stage type regulator comprising a high-pressure regulator and a low-pressure regulator disposed at a downstream side of the high-pressure regulator, and the negative pressure supplying passage connects respective diaphragm chambers of the high-pressure regulator and the low-pressure regulator to the intake pipe.
2. A gas fuel supply system for supplying gas fuel to an internal combustion engine, comprising:
a fuel supply passage for supplying the gas fuel to an injector; and
source pressure control means for controlling pressure of the gas fuel supplied to the injector through the fuel supply passage by using negative pressure in an intake pipe such that the pressure of the gas fuel increases if the negative pressure in the intake pipe decreases, and the pressure of the gas fuel decreases if the negative pressure in the intake pipe increases;
wherein the source pressure control means comprises a diaphragm type regulator provided in the fuel supply passage, and a negative pressure supplying passage which connects a diaphragm chamber of the regulator to the intake pipe;
wherein a throttle valve is provided in the intake pipe for adjusting an amount of intake air, and the negative pressure supplying passage connects the diaphragm chamber of the regulator to a downstream side of the throttle valve in the intake pipe; and
wherein the regulator is a two-stage type regulator comprising a high-pressure regulator and a low-pressure regulator disposed at a downstream side of the high-pressure regulator, and the negative pressure supplying passage connects a diaphragm chamber of the low-pressure regulator to the intake pipe.
3. A gas fuel supply system for supplying gas fuel to an internal combustion engine, comprising:
a fuel supply passage for supplying the gas fuel to an injector; and
source pressure control means for controlling pressure of the gas fuel supplied to the injector through the fuel supply passage by using negative pressure in an intake pipe such that the pressure of the gas fuel increases if the negative pressure in the intake pipe decreases, and the pressure of the gas fuel decreases if the negative pressure in the intake pipe increases;
wherein the source pressure control means comprises a flow rate control valve which is provided in the fuel supply passage and comprises a valve element for opening and closing a passing hole for the gas fuel, a negative pressure receiving part connected to the valve element, a negative pressure applied chamber defined in a back side of the negative pressure receiving part, and an adjustment spring for urging the valve element in a closing direction, wherein the pressure in the negative pressure applied chamber acts to move the valve element in an opening direction, and a negative pressure supplying passage connects the negative pressure applied chamber of the flow rate control valve to the intake pipe.
4. The gas fuel supply system as defined in claim 3 , wherein a throttle valve is provided in the intake pipe for adjusting an amount of intake air, and the negative pressure supplying passage connects the negative pressure applied chamber of the flow rate control valve to a downstream side of the throttle valve in the intake pipe.
5. The gas fuel supply system as defined in claim 4 , wherein a regulator for decompressing the pressure of the gas fuel to a predetermined pressure is provided in the fuel supply passage, and the flow rate control valve is provided in a downstream side of the regulator in the fuel supply passage.