An engine speed of work vehicle can be controlled automatically based on various conditions. For example, an excavator can include a first sensor for detecting a vehicle characteristic and transmitting an associated first sensor signal, and a second sensor for detecting an engine characteristic and transmitting an associated second sensor signal. The excavator can include a control circuit for receiving the sensor signals. The control circuit can determine the vehicle characteristic based on the first sensor signal and the engine characteristic based on the second sensor signal. The control circuit can determine that at least one vehicle condition of multiple vehicle conditions is satisfied based on the vehicle characteristic, and that at least one engine condition of multiple engine conditions is satisfied based on the engine characteristic. The control circuit can transmit a signal configured to cause the excavator to reduce an engine speed to a low idle engine speed.

A control system of an engine including a cylinder, an intake passage, and an exhaust passage is provided, that includes a fuel injector for injecting fuel into the cylinder, an exhaust gas recirculation (EGR) passage communicating the intake passage with the exhaust passage and for recirculating, as EGR gas, a portion of exhaust gas in the exhaust passage back to the cylinder, an EGR valve capable of controlling an EGR ratio by changing an EGR gas amount recirculated to the cylinder, a water injector for injecting water into the cylinder, and a controller. The controller controls the EGR valve to set a target EGR ratio according to an engine operating state so as to bring an actual EGR ratio to the target EGR ratio, and when the target EGR ratio is increased, the controller controls the water injector to increase an amount of the water injected into the cylinder.

A control apparatus for an internal combustion engine is provided. The control apparatus includes an ECU. The ECU is configured to change, in a stepped manner, an air-fuel ratio of the internal combustion engine so as to change over a combustion mode of the internal combustion engine between lean combustion and stoichiometric combustion, when an operating point of the internal combustion engine satisfies a first changeover condition that is defined by a rotational speed and a torque of the internal combustion engine. The first changeover condition is defined by the rotational speed and the torque that correspond to a predetermined intake air amount at which a thermal efficiency of the internal combustion engine is maintained before and after changeover of the combustion mode.

A target air amount for achieving a requested torque is back-calculated from the requested torque using a parameter that provides a conversion efficiency of an air amount to torque. The value of the parameter gradually changes to lower the conversion efficiency as the requested torque decreases from a second reference value towards a first reference value. The first reference value is calculated based on the engine speed. The second reference value is calculated based on an air amount with which the first reference value is achieved under a second air-fuel ratio, and a first air-fuel ratio. The target air-fuel ratio is set to the first air-fuel ratio when the requested torque is greater than the first reference value, and is switched from the first air-fuel ratio to the second air-fuel ratio when the requested torque decreases to a value equal to or less than the first reference value.

A control device for an internal combustion engine includes a throttle valve opening degree detector, an air bypass valve controller, and a torque reduction controller. The throttle valve opening degree detector detects an opening degree of a throttle valve which is provided downstream with respect to a compressor of a supercharger. The air bypass valve controller opens an air bypass valve based on a reduction change in the opening degree of the detected throttle valve. The air bypass valve is configured to open and close a bypass path. The torque reduction controller controls the throttle valve to reduce the opening degree of the throttle valve while an automatic transmission connected to the internal combustion engine is in an acceleration shifting in order to execute a torque reduction control. The air bypass valve controller maintains the air bypass valve in a close state during the torque reduction control.

A vehicle control apparatus is provided that can maintain an automatic engine stop function when an abnormality occurs in a preceding vehicle following control function. The vehicle control apparatus includes a first control unit configured to include a preceding vehicle following control function to control vehicle speed, based on a traveling state of a preceding vehicle, and to output a prohibition request to an automatic engine stop function; and a second control unit configured to include the automatic engine stop function, and to maintain the automatic engine stop function, contrary to the prohibition request output from the first control unit, when an abnormality occurs in the preceding vehicle following control function.

The condensed water processing device determines (S2) whether the pH of condensed water stored in the condensed water tank is smaller than a threshold value (t). When the pH of condensed water is smaller than the threshold value (t), the supply quantity of urea water being supplied to the upstream side of the NOx catalyst is increased (S7) so that the supply quantity is larger than that in normal control (S4) executed when the pH of the condensed water is equal to or more than the threshold value (t).

A method to control a supercharged internal combustion engine by means of a turbocharger provided with a turbine and a compressor which compresses the air taken in; the control method includes the steps of determining the instantaneous rotation speed of the turbocharger; and calculating the average power delivered by the turbine as a function of the absolute value of the j-th harmonic component of the instantaneous rotation speed of the turbocharger and of the instantaneous rotation speed of the turbocharger; and controlling the supercharged internal combustion engine as a function of the average power delivered by the turbine.

Methods and systems are provided for improving combustion stability, in particular during transient operations such as tip-out to lower load conditions, when EGR is being purged. Until a desired LP-EGR rate is achieved, fuel may be delivered as a split injection with at least an intake stroke injection and a compression stroke injection. Subsequently, single fuel injection may be resumed.

A method for carrying out a gas exchange in a cylinder of an internal combustion engine is provided. The cylinder is connected to a gas line section via a valve. An actuator adjusts a gas pressure in the gas line section. The valve closes at a fixed point in time in a working cycle of the internal combustion engine in case of a constant torque of the internal combustion engine. The method includes the steps of recognizing a torque change request; determining a target value for the gas pressure in the gas line section in dependence on the torque change request; and determining a variable point in time for closing the valve as a result of the torque change request, wherein the variable point in time is shifted in the working cycle relative to the fixed point in time in dependence on the target value of the gas pressure.