Internal combustion engine having a fuel injection system

An internal combustion engine having a fuel injection system which delivers fuel directly into a combustion chamber for mixing with charge air delivered separately to the combustion chamber via an inlet valve, the fuel injection system comprising:

• a fuel injector which functions as a positive displacement pump and dispenses in each operation thereof a set quantity of fuel;
• a mixing chamber into which the fuel injector dispenses fuel;
• and
• a gas supply passage for supplying gas to the mixing chamber to entrain the fuel dispensed into the mixing chamber in a flow of gas which passes through the mixing chamber into the charge air;
• wherein:
• the mixing chamber is connected to the combustion chamber to deliver fuel and gas into the combustion chamber separately from the charge air and a depression in the combustion chamber is used to draw gas through the gas supply passage into the combustion chamber;
• the inlet valve is a cylinder head poppet valve which controls flow of charge air into the combustion chamber and the inlet valve is kept closed for an initial part of an intake stroke of the engine so that the depression is created in the combustion chamber;
• and
• the fuel injector dispenses an amount of fuel which is fixed for each and every operation of the injector;
• and
• an electrically-operated valve is provided to control flow of gas from the gas supply passage through the mixing chamber.

An internal combustion engine having a fuel injection system which delivers fuel directly into a combustion chamber for mixing with charge air delivered separately to the combustion chamber via an inlet valve, the fuel injection system comprising:

• a fuel injector which functions as a positive displacement pump and dispenses in each operation thereof a set quantity of fuel;
• a mixing chamber into which the fuel injector dispenses fuel;
• and
• a gas supply passage for supplying gas to the mixing chamber to entrain the fuel dispensed into the mixing chamber in a flow of gas which passes through the mixing chamber into the charge air;
• wherein:
• the mixing chamber is connected to the combustion chamber to deliver fuel and gas into the combustion chamber separately from the charge air and a depression in the combustion chamber is used to draw gas through the gas supply passage into the combustion chamber;
• and
• the inlet valve is a cylinder head poppet valve which controls flow of charge air into the combustion chamber and the inlet valve is kept closed for an initial part of an intake stroke of the engine so that the depression is created in the combustion chamber;
• and
• fuel and gas leaving the mixing chamber pass through an atomising nozzle prior to mixing with the charge air;
• a cylinder head exhaust valve is provided to control exhaust of the combusted gases from the combustion chamber, the exhaust valve being separate from and spaced from the inlet valve and the atomising nozzle;
• and
• an electrically-operated valve is provided to control flow of gas from the gas supply passage through the mixing chamber.

An internal combustion engine having a fuel injection system which delivers fuel directly into a combustion chamber for mixing with charge air delivered separately to the combustion chamber via an inlet valve, the fuel injection system comprising:

• a fuel injector which functions as a positive displacement pump and dispenses in each operation thereof a set quantity of fuel;
• a mixing chamber into which the fuel injector dispenses fuel;
• and
• a gas supply passage for supplying gas to the mixing chamber to entrain the fuel dispensed into the mixing chamber in a flow of gas which passes through the mixing chamber into the charge air;
• wherein:
• the mixing chamber is connected to the combustion chamber to deliver fuel and gas into the combustion chamber separately from the charge air and a depression in the combustion chamber is used to draw gas through the gas supply passage into the combustion chamber;
• the inlet valve is a cylinder head poppet valve which controls flow of charge air into the combustion chamber and the inlet valve is kept closed for an initial part of an intake stroke of the engine so that the depression is created in the combustion chamber;
• and
• the fuel injector dispenses an amount of fuel which is fixed for each and every operation of the injector;
• the fuel and gas leaving the mixing chamber pass through an atomising nozzle prior to mixing with the charge air;
• a cylinder head exhaust valve is provided to control exhaust of the combusted gases from the combustion chamber, the exhaust valve being separate from and spaced from the inlet valve and the atomizing nozzle;
• and
• an electrically-operated valve is provided to control flow of gas from the gas passage through the mixing chamber, the electrically-operated valve comprising a pintle operable in the atomising nozzle.

A method of delivering fuel into a combustion chamber separately from charge air delivered to the combustion chamber via an inlet valve, the method comprising the steps of:

• dispensing a set quantity of fuel from a fuel injector to a mixing chamber;
• and
• entraining the fuel in the mixing chamber in a flow of gas, with the flow delivering the fuel to the combustion chamber via an atomising nozzle;
• and
• controlling exhaust of combusted gases from the combustion chamber using a cylinder head exhaust valve separate from and spaced from the inlet valve and the atomizing nozzle;
• wherein:
• a depression is created in the combustion chamber in an early part of an intake stroke of the engine by keeping closed the inlet valve and the depression is used to draw through the atomising nozzle the gas used to entrain the dispensed fuel;
• and
• an electrically-operated valve is used to control flow of gas in the mixing chamber.