A method for ascertaining a viscosity of a fuel with the aid of an electric fuel pump which is integrated into a fuel circuit including an overflow valve which includes a permanently open discharge channel, a fuel supply and delivery being adjusted with the aid of the electric fuel pump in the fuel circuit at a specific pressure and the viscosity of the fuel being ascertained by taking into account a delivery rate of the electric fuel pump.

Methods and systems are provided for temperature control of a high pressure pump (HPP) of a direct injection system. When direct injection is disabled, the HPP and the associated direct injectors are intermittently operated when the HPP temperature rises above a modeled threshold temperature. The HPP and injectors are operated until the HPP temperature falls below the modeled threshold temperature.

The purpose of the present invention is to provide a control device for an internal combustion engine with which it is possible to favorably control an engine even if there could occur a difference in temperatures of fuel injected into respective cylinders. The present invention is a control device for an internal combustion engine, for controlling an internal combustion engine provided with fuel injection valves for directly injecting fuel respectively to a plurality of cylinders, wherein: the control device is provided with a fuel temperature acquiring means for acquiring respective temperatures of fuel injected to each of the cylinders; and at least one of a fuel injection valve control amount, ignition control amount, and intake and exhaust valve control amount of each of the cylinders is set in accordance with the respective temperatures of fuel acquired by the fuel temperature acquiring means. Alternatively, the present invention is a control device for an internal combustion engine, for controlling an internal combustion engine provided with fuel injection valves for directly injecting fuel respectively to a plurality of cylinders, wherein the control device is provided with a valve-closing time detecting means for detecting a valve-closing time of a valve body of each of the fuel injection valves, and a fuel temperature estimating means for estimating the temperature of fuel on the basis of the valve-closing duration of the valves detected by the valve-closing time detecting means.

In some embodiments, a vehicle includes a temperature monitoring controller. The temperature monitoring controller is a processor, control module, or other suitable hardware that is configured to receive temperature sensor values from an engine control module (ECM) when an ignition bus is in a powered on state, and to decide when the engine should be automatically started in order to maintain a temperature above a low temperature threshold. The temperature monitoring controller periodically causes an ignition bus of the vehicle to be placed in the powered on state when the engine is shut down in order to collect temperature sensor values. The temperature monitoring controller determines whether to automatically start the engine, and if not, determines how long to wait before collecting temperature sensor values again based on a rate of change of the temperature sensor values.

A working machine includes: a machine body; a prime mover that is mounted on the machine body; a fuel cylinder that contains a fuel; a vaporizer that vaporizes the fuel sent from the fuel cylinder and supplies the fuel to the prime mover; a temperature detector that detects a temperature correlating with a decrease in the temperature of the vaporizer; and a controller that imposes restraint on the flow rate of the fuel flowing from the vaporizer to the prime mover when the temperature detected by the temperature detector is lower than or equal to a first temperature.

A control system includes an internal combustion engine and a control device. The internal combustion engine includes a pressurization device. The pressurization device includes a housing having a cylindrical shape, a piston, a pressurization chamber, a piston chamber, a pressurization control chamber, and a switching device configured to selectively connect the pressurization control chamber with a high pressure fuel channel or a low pressure fuel channel. The control device estimates the temperature of the low pressure fuel channel, When the estimated temperature of the low pressure fuel channel is lower than the temperature of the pressurization device, and the temperature of the pressurization device is higher than a predetermined cooling request temperature, the control device controls the switching device to connect the pressurization control chamber with the low pressure fuel channel.

A fuel temperature estimation device that can improve the estimation accuracy of a fuel temperature in each part of a fuel channel, is provided. In the invention, the fuel temperature estimation device estimates the fuel temperature of each part of the fuel channel in a vehicle (for example, an injection nozzle, a pressure accumulator, a high-pressure pump), and includes a flow rate measuring device that measures a fuel flow rate of a fuel return system of the fuel channel and a controller. The controller includes a fuel temperature correction unit that corrects an estimated fuel temperature in a fuel injection system based on the fuel flow rate of the fuel return system, and has a function of estimating the fuel temperature using the fuel flow rate of the fuel return system as a parameter.

A method for determining a quantity of fuel injected into a cylinder of an internal combustion engine including an injection rail includes: measuring the pressure prevailing in the injection rail during fuel injection from the rail into a cylinder; filtering the pressure measurement; determining the relative minimum and maximum points of the filtered pressure curve; insofar as a first (Pdrop1) pressure drop followed by a pressure rise and then a second (Pdrop2) pressure drop is identified, determining a physical quantity that makes it possible to characterize the first pressure drop and the second pressure drop; and determining the quantity of fuel injected by applying the bulk modulus for the two pressure drops identified as a function of the temperature in the injection rail.

Methods and systems are provided for temperature control of a high pressure pump (HPP) of a direct injection system. When direct injection is disabled, the HPP and the associated direct injectors are intermittently operated when the HPP temperature rises above a modeled threshold temperature. The HPP and injectors are operated until the HPP temperature falls below the modeled threshold temperature.

A heater control apparatus of a fuel filter for a vehicle includes a heater mounted within a fuel filter; a relay for a heater power source supplying or interrupting power of a battery to or from the heater; a fuel temperature detection sensor mounted on an engine and detecting a temperature of a fuel; and an engine electronic control unit (ECU) for switching on and off the relay based on a detection signal of the fuel temperature detection sensor.