초록 ▼

A dual fuel engine (2) is provided which is supplied with diesel fuel and at least one secondary fuel, such as LPG. The engine (2) has a plurality of cylinders (4, 6, 8, 10) in which pistons reciprocate. Each cylinder has diesel injectors (4A, 6A, 8A, 10A) for injecting the diesel fuel into the cyli

A dual fuel engine (2) is provided which is supplied with diesel fuel and at least one secondary fuel, such as LPG. The engine (2) has a plurality of cylinders (4, 6, 8, 10) in which pistons reciprocate. Each cylinder has diesel injectors (4A, 6A, 8A, 10A) for injecting the diesel fuel into the cylinder during an appropriate stroke of the piston and an air inlet valve (4C, 6C, 8C, 10C) which opens during the appropriate stroke of the piston to permit air flow therethrough. Each cylinder is further provided with LPG injectors (4B, 6B, 8B, 10B) for injecting the secondary fuel into the cylinders. The LPG injectors are independent to and separate from the diesel fuel injectors. The LPG and diesel fuel injectors are also independently controlled.

대표청구항 ▼

The invention claimed is: 1. A dual-fuel engine, the engine being supplied with diesel fuel and at least one secondary fuel, the engine comprising: one or more cylinders in which one or more pistons, reciprocate; diesel injection means provided to each of the one or more cylinders for injecting the

The invention claimed is: 1. A dual-fuel engine, the engine being supplied with diesel fuel and at least one secondary fuel, the engine comprising: one or more cylinders in which one or more pistons, reciprocate; diesel injection means provided to each of the one or more cylinders for injecting the diesel fuel into the cylinder during an appropriate stroke of the piston; at least one air inlet valve provided to each of the one or more cylinders, the at least one valve moving to an open condition during the appropriate stroke of the piston to permit air flow therethrough; secondary fuel injection means provided to each of the one or more cylinders for injecting the secondary fuel into the cylinders, the secondary fuel injection means being independent of the diesel fuel injection means and air inlet valves; an electronic control unit (ECU) including micro-processing means for dynamically controlling one or more engine operating characteristics; and vaporizing means for reducing liquid secondary fuel to gas upstream of the secondary fuel injection means to allow delivery of the secondary fuel in gaseous form to the secondary fuel injection means, wherein the vaporizing means is under the control of the ECU to allow dynamic control of delivery of the gaseous secondary fuel to the secondary fuel injection means. 2. An engine according to claim 1 characterized in that control of the operation of the secondary fuel injection means is independent of the operation of the diesel injection means. 3. An engine according to claim 1 characterized in that the secondary fuel injection means are controlled to introduce the secondary fuel in the one or more cylinders on the appropriate stroke of the piston reciprocating therein. 4. An engine according to claim 1 characterized in that the engine is provided with two fuel supply tanks for the diesel fuel and secondary fuel respectively, each fuel being delivered to the engine through separate supply means. 5. An engine according to claim 1 characterized in that injection of the secondary fuel into the one or more cylinders occurs substantially simultaneously to injection of the diesel fuel into said cylinders. 6. An engine according to claim 1 characterized in that means are provided for sensing and/or controlling one or more engine operating conditions. 7. An engine according to claim 6 characterized in that sensing means are provided for sensing any or any combination of exhaust emissions, exhaust gas particulate density, throttle position, temperature of the secondary fuel being delivered to the engine and/or the engine itself, turbo pressure, airflow velocity and pressure, secondary fuel gauge, engine speed, position of a flow control means and/or position of the diaphragm in the vaporizing means. 8. An engine according to claim 6 characterized in that flow control means are provided for regulating the amount of secondary fuel flowing into the engine. 9. An engine according to claim 8 characterized in that control of the flow of the secondary fuel to the secondary fuel injection means by said flow control means is regulated dynamically according to one or more sensed engine operating characteristics. 10. An engine according to claim 8 characterized in that the flow control means are provided in fuel supply pipes supplying secondary fuel to the engine. 11. An engine according to claim 8 characterized in that an output of the flow control means is coupled to an input of a multi-output divider for dividing a singular flow of secondary fuel into a plurality of flows, the number of flows corresponding to the number of cylinders in the engine and each of said flows being coupled to the secondary fuel injection means. 12. An engine according to claim 8 characterized in that the flow control means includes a piston, the position of which is changed to alter the amount of secondary fuel flowing therethrough. 13. An engine according to claim 8 characterized in that the ECU controls both the flow control means and the diaphragm in the vaporizing means for regulating the flow of the secondary fuel through each component. 14. An engine according to claim 1 characterized in that the ECU includes at least one of: a) one or more inputs in communication with sensing means disposed in and/or around the engine for sensing one or more operating characteristics thereof b) means capable of receiving and/or processing a user input c) calibration means through which maintenance and adjustment of one or more algorithms and/or operating parameters of the ECU can be achieved d) one or more outputs for displaying data relating to the operating characteristics of the engine; and e) one or more outputs for connection to one or more dynamically adjustable components of the engine for dynamic control thereof during engine operation. 15. An engine according to claim 14 characterized in that calculations resulting from executing the one or more algorithms are used to set the vaporizer diaphragm or piston of the flow control means to an optimum level for the detected operating conditions. 16. An engine according to claim 1 characterized in that the ECU controls the flow of secondary fuel through a diaphragm in the vaporizing means and/or the temperature of a heating element provided therein. 17. An engine according to claim 1 characterized in that operation of the ECU is substantially continuous. 18. An engine according to claim 1 characterized in that the ECU includes memory means for storing one or more pre-determined engine operating conditions therein. 19. An engine according to claim 18 characterized in that the memory means includes one or more algorithms which can be executed by processing means when pre-determined conditions are met. 20. An engine according to claim 19 characterized in that said pre-determined conditions include any or any combination of when the engine is started, when the secondary fuel runs out and/or when the load on the engine reaches a pre-determined level or is outside a pre-determined level. 21. An engine according to claim 19 characterized in that at least one recalibration algorithm is provided for allowing the ECU to adjust its operation as the engine and its associated component undergo wear. 22. An engine according to claim 18 characterized in that data input from sensing means to the ECU is compared to pre-determined engine operating conditions and the ECU outputs data to adjust the flow of the secondary fuel to the engine and/or one or more other engine operating parameters. 23. An engine according to claim 1 characterized in that a secondary fuel limiter is provided to prevent "over-powering" of the engine. 24. An engine according to claim 1 characterized in that emergency shut off valves are provided in fuel supply means which deliver the diesel fuel and the secondary fuel to the engine. 25. An engine according to claim 1 characterized in that traction control means are provided and, on detection of a loss of traction, the supply of secondary fuel to the engine is reduced or cut off. 26. An engine according to claim 1 characterized in that the secondary fuel is liquefied petroleum gas (LPG). 27. A method of converting a diesel engine to a dual-fuel engine, the engine being supplied with diesel fuel and at least one secondary fuel, the engine comprising: one or more cylinders in which one or more pistons reciprocate; injection means for injecting diesel fuel into the cylinder during an appropriate stroke of the piston; and at least one air inlet valve, said valve moving to an open condition during said appropriate stroke of the piston to permit air flow therethrough, the method comprising: providing secondary fuel injection means to each of the one or more cylinders for injecting the secondary fuel into the cylinders, the secondary fuel injection means being provided independently to the diesel fuel injection means and air inlet valves; providing an electronic control unit (ECU) including micro-processing means for dynamically controlling one or more engine characteristics; and providing vaporizing means for reducing liquid secondary fuel to gas upstream of the secondary injection means to allow delivery of the secondary fuel in gaseous form to the secondary fuel injection means, the vaporizing means being under the control of the ECU to allow dynamic control of delivery of the gaseous secondary fuel to the secondary fuel injection means.