A system for monitoring fuel additives on board a vehicle includes a fuel line carrying fuel from a fuel source to an engine; a fuel additive sensor configured to measure concentration of additives in fuel at a point along the fuel line; a fuel additive dispenser connected in parallel to the fuel line; at least one flow control device for controlling an amount of flow from the fuel line into the fuel additive dispenser; and a controller configured to receive input from the fuel additive sensor and to control the flow control device to adjust the amount of the flow from the fuel line into the fuel additive dispenser.

A fuel pump for a liquid fuel water injection system of a motor vehicle is provided. The fuel pump includes a low-pressure pump that mixes water from a water tank of the motor vehicle with liquid fuel from a fuel tank of the motor vehicle to a liquid fuel water emulsion and provides the liquid fuel water emulsion at a low pressure. A high-pressure pump is in fluid communication with the low-pressure pump and compresses the liquid fuel water emulsion from the low pressure to a high pressure for injecting the liquid fuel water emulsion into an internal combustion engine of the motor vehicle via an injection rail of the motor vehicle. A pump drive drives the low-pressure pump and the high-pressure pump synchronously with a pump frequency independently from an engine speed of the internal combustion engine of the motor vehicle.

A method for detecting reverse flow for a dual fuel engine is disclosed. The engine may include an intake manifold, a liquid fuel supply line and a gaseous fuel supply line, the gaseous fuel supply line including a gaseous fuel supply and a gaseous fuel rail. The method may include: operating the dual fuel engine in a liquid fuel only mode via the liquid fuel supply line; determining a reverse flow in the gaseous fuel supply line; and outputting an indication of reverse flow in response to the determination of reverse flow.

Electronic fuel injection for an internal combustion engine maintains an operator-specified air-to-fuel ratio during engine operations in high-speed, high-volume, mixed fuel applications. A microprocessor-based controller executes a program stored in memory to calculate a fuel flow value as a function of the specified air-to-fuel ratio and specified density ratio of mixed fuels. The controller outputs a control signal to a variable fuel flow relief valve and receives feedback from an engine fuel flow sensor. The controller adjusts the control signal until the feedback matches the fuel flow value. The program optimizes the fuel flow value by accounting for engine air flow, water vapor density, and dry air density effects in the calculation, based on signals received by the controller from various environmental sensors. The system has particular application in dragster engines that burn a mixture of nitromethane and methanol.

An engine control unit of a multi-fuel is provided. The engine consumes a mixture of a first combustion fuel and a second combustion fuel. The engine control unit includes hardware circuitry that includes one or more processors configured to calculate an autoignition delay of the mixture of the air and the second combustion fuel based on current operating conditions of the multi-fuel engine. The one or more processors also are configured to calculate an upper limit on an amount of the second combustion fuel that is supplied to the multi-fuel engine based on the autoignition delay that is calculated.

A fuel pump for a liquid fuel water injection system of a motor vehicle is provided. The fuel pump includes a low-pressure pump that mixes water from a water tank of the motor vehicle with liquid fuel from a fuel tank of the motor vehicle to a liquid fuel water emulsion and provides the liquid fuel water emulsion at a low pressure. A high-pressure pump is in fluid communication with the low-pressure pump and compresses the liquid fuel water emulsion from the low pressure to a high pressure for injecting the liquid fuel water emulsion into an internal combustion engine of the motor vehicle via an injection rail of the motor vehicle. A pump drive drives the low-pressure pump and the high-pressure pump synchronously with a pump frequency independently from an engine speed of the internal combustion engine of the motor vehicle.

A method for operating a common-rail fuel supply system of an internal combustion engine includes determining, dependent on an operating point of the engine, a set point rate of delivery of the high-pressure pumping device, and a set point pressure for the pressure storage system under high pressure, determining, dependent on a deviation between the set point pressure and an actual pressure in the pressure storage system, for a first part quantity of the throttle valves a closed-loop control portion for the position of the respective throttle valve, and activating the first part quantity of the throttle valves with the closed-loop control portion in addition to open-loop control for only the respective throttle valve of the first part quantity of the throttle valves. The, or each, throttle valve of a second part quantity of the throttle valves is exclusively activated with the open-loop control portion.

An engine operable in a premixed combustion system and a diffusion combustion system. The engine includes a main fuel injection valve, a pilot fuel injection valve, a liquid fuel tank, a main fuel supply path, a pilot fuel supply path, a pilot fuel filter, a pilot fuel high-pressure pump, a pilot fuel tank, and a pilot fuel supply pump. The pilot fuel tank stores pilot fuel sent from the pilot fuel high-pressure pump and not injected by the pilot fuel injection valve. This pilot fuel is sent to an automatic backwash filter and a pilot fuel filter while not passing through the liquid fuel tank.

A fuel separation system includes a fuel separator configured to receive a fuel stream and separate the fuel stream, based on a volatility of the fuel stream, into a vapor stream defined by a first auto-ignition characteristic value and a first liquid stream defined by a second auto-ignition characteristic value, the second auto-ignition characteristic value greater than the first auto-ignition characteristic value; and a heat exchanger fluidly coupled between a fuel input of the fuel stream and the fuel separator, the heat exchanger configured to transfer heat from the vapor stream to the fuel stream, and output a heated fuel stream to the fuel separator and a second liquid stream defined by the first auto-ignition characteristic value.

Systems and methods for operating a fuel system that includes two separate fuel tanks are disclosed. In one example, fuel may be purged from a fuel rail in response to Reid vapor pressure of a fuel so that engine starting may be improved. A fuel with a higher Reid vapor pressure may be pumped into the fuel rail when the engine is expected to be cold started.