Systems, apparatus and methods include control techniques for controlling operation of pre-mixed internal combustion engines in response to a load shedding event. The control techniques determine, in response to the load shedding event, a number of cycles in which to skip combustion of the fuel in the at least one cylinder based on an air-fuel ratio limit in the exhaust flow, prevent combustion of the fuel in the at least one cylinder during the number of skipped cycles, and combust the fuel in the at least one cylinder each time the number of skipped cycles are complete.

The present invention relates to a pressure coupled control method and system for diffusion combustion of a natural gas engine, the method comprising: S11: detecting an operating condition of a natural gas engine; S12: an electronic control unit calculating a target diesel fuel pressure value flowing into a fuel rail of the natural gas engine according to the operating condition, and detecting an actual diesel fuel pressure value flowing into the fuel rail by means of a diesel pressure sensor in the fuel rail; S13: the electronic control unit calculating a target natural gas pressure value flowing into a gas rail of the natural gas engine according to the actual diesel fuel pressure value, and regulating a natural gas flowing into the gas rail by means of a signal of a gas rail pressure sensor in the gas rail; S14: after the target diesel fuel pressure value and the target natural gas pressure value are established, successively injecting high pressure diesel fuel and a high pressure natural gas into a gas cylinder; S15: detecting in real time a real-time operating condition of the natural gas engine, and promptly regulating the target diesel fuel pressure value and the target natural gas pressure value according to the real-time operating condition. The present invention improves diffusion combustion efficiency by means of the pressure coupled control of diesel fuel and natural gas.

A method and a system for controlling combustion of a natural gas engine. The method includes: determining, based on a current operation parameter of a natural gas engine, an operation state of the natural gas engine, and calculating a total injection quantity of natural gas and pilot diesel required by the natural gas engine in the operation state; adopting a direct injection diffusion-combustion mode in a case that the operation state is an idle state or a low load state; adopting a natural gas homogeneous hybrid active control compression-ignition mode in a case that the operation state is a medium load state; configuring the total injection quantity into three parts including a compression-ignition natural gas injection quantity, a pilot diesel injection quantity, and a diffusion-combustion natural gas injection quantity in a case that the operation state is a high load state, and sequentially injecting them into a combustion chamber.

A fuel control system can operate an internal combustion engine to selectively combust a first fuel, such as diesel, during a single fuel mode and to combust the first fuel and a second fuel, such natural gas, during a fuel substitution mode. An in-cylinder parameter sensor is in communication with the combustion chamber of the internal combustion engine to measure an in-cylinder parameter such as, for example, the indicated mean effective pressure, during combustion of the first fuel during the single fuel mode. The fuel control system utilizes the in-cylinder parameter to determine a first fuel quantity error and can adjust delivery of the first fuel to correct for the first fuel quantity error during the single fuel and fuel substitution modes. The fuel control system can also use the first fuel quantity error to determine and adjust for a second fuel quantity error.

Systems, methods and apparatus for controlling operation of dual fuel engines are disclosed that regulate the fueling amounts provided by a first fuel and a second fuel during operation of the engine. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The fueling amounts are controlled to improve operational outcomes of the duel fuel engine.

The invention involves a system and method for providing a liquid fuel or a liquid and gaseous fuel to a diesel or Otto cycle engine for operation of the engine. The system includes a primary electronic control module (ECM), which monitors engine sensors and contains a first three-dimensional fuel map for the liquid fuel. A second ECM is connected for bi-directional transfer of information to the first ECM, the second ECM contains a second three-dimensional fuel map for delivery of the gaseous fuel through a secondary gaseous fuel injection assembly. The bi-directional communication between the two ECMs while monitoring the engine sensors allows both ECMs to learn an efficient fuel map for delivery of both fuels in the same cycle for improved efficiency, reduction in slip and lower emissions.

Starting a gaseous fuelled engine employing a pilot fuel at cold temperatures is challenging due to reduced ignitability and combustion efficiency of the fuel(s), and the increased viscosity of engine oil. A technique for starting a compression ignition, gaseous fuelled internal combustion engine employing a pilot fuel comprises determining one of a normal start condition and a cold start condition; during the normal start condition, introducing the pilot fuel into a combustion chamber of the internal combustion engine when the pilot fuel pressure rises above a first pressure; during the cold start condition, introducing the pilot fuel into the combustion chamber when the pilot fuel pressure rises above a second pressure that is higher than the first pressure; and selectively introducing the gaseous fuel into the combustion chamber.

Nonwoven abrasive articles comprise a nonwoven abrasive member having an overlayer composition comprising a fatty acid metal salt disposed thereon adjacent to a working surface. The nonwoven abrasive member comprises abrasive particles adhered to a fiber web by a binder. The abrasive particles may be exposed and/or the nonwoven abrasive member may have suitable frictional properties. Methods of making the same are also disclosed.

The present invention relates to a pressure coupled control method and system for diffusion combustion of a natural gas engine, the method comprising: S11: detecting an operating condition of a natural gas engine; S12: an electronic control unit calculating a target diesel fuel pressure value flowing into a fuel rail of the natural gas engine according to the operating condition, and detecting an actual diesel fuel pressure value flowing into the fuel rail by means of a diesel pressure sensor in the fuel rail; S13: the electronic control unit calculating a target natural gas pressure value flowing into a gas rail of the natural gas engine according to the actual diesel fuel pressure value, and regulating a natural gas flowing into the gas rail by means of a signal of a gas rail pressure sensor in the gas rail; S14: after the target diesel fuel pressure value and the target natural gas pressure value are established, successively injecting high pressure diesel fuel and a high pressure natural gas into a gas cylinder; S15: detecting in real time a real-time operating condition of the natural gas engine, and promptly regulating the target diesel fuel pressure value and the target natural gas pressure value according to the real-time operating condition. The present invention improves diffusion combustion efficiency by means of the pressure coupled control of diesel fuel and natural gas.

Systems, methods and apparatus for controlling operation of dual fuel engines are disclosed that regulate the fuelling amounts provided by a first fuel and a second fuel during operation of the engine. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The fuelling amounts are controlled to improve operational outcomes of the duel fuel engine.