A four-stroke internal combustion engine is disclosed comprising an exhaust valve control arrangement with an exhaust valve phase-shifting device configured to phase-shift control of the at least one exhaust valve to a state where the at least one exhaust valve is controlled in such a way that it is opened during the expansion stroke of the engine and closed during the exhaust stroke of the engine, in order to achieve engine-braking via compression in the cylinders during the exhaust stroke. An inlet valve control arrangement comprises an inlet valve phase-shifting device configured to regulate the amount of air pumped through the engine during the engine braking by regulating the phase-shift of the at least one inlet valve. The present disclosure also relates to a vehicle comprising an engine and method of controlling an engine, a computer program and a computer program for performing a method of controlling an engine.

A method for operating an internal combustion engine having an engine with a first number of cylinders and a second number of cylinders and a supercharger arrangement, wherein a charge air flow supplied to the engine is compressed by means of at least one compressor and at least one turbine is acted on by an exhaust gas flow discharged from the engine. In a main operating mode, the engine operates the first number of cylinders in two-stroke operation and the second number of cylinders in four-stroke operation. A scavenging gradient of the engine is greater for the cylinders operated in the two-stroke operation than for the cylinders operated in the four-stroke operation.

The invention concerns a method for controlling the fuel supply to an internal combustion engine at start-up. The fuel supply system can be set in at least two start modes, a lean mode and a rich mode, and the selection of mode is based on an evaluation of a previous start attempt or successful run. The invention also concerns a carburetor (10) having a fuel supply system including a main fuel path (13) with an actively controlled fuel valve (26) and an idling fuel path (14) branching off from the main fuel path (13) downstream of the valve (26). The fuel supply system further includes a start fuel line (23, 423) starting upstream (FIG. 1) or downstream (FIG. 4) of the fuel valve (26) and ending in at least one start fuel outlet near and downstream of a choke valve.

A utility engine air-to-fuel ratio control method in which during an initial or early part of a period of engine continuous operation its stability of operation is determined and if sufficiently stable a test of the air-to-fuel ratio of the air-fuel mixture supplied to the engine is performed and if need be changed to a new air-to-fuel ratio supplied to the engine during the remainder of the period of engine continuous operation. If the engine operation is not sufficiently stable the test is not started or if started is aborted.

A multiple-cylinder diesel engine system comprises an intake valve and an exhaust valve for each of the multiple cylinders. A valve control system is connected to selectively deactivate an intake valve and an exhaust valve for a selected cylinder. A fuel injection control system is connected to selectively deactivate fuel injection to the selected cylinder while increasing fuel to firing cylinders. The multiple cylinder diesel engine enters a cylinder deactivation mode whereby the valve control system deactivates the intake valve and the exhaust valve and the fuel injection control system deactivates the fuel injection to the cylinder while continuing to fire other cylinders of the multiple cylinder diesel engine. The valve control system selectively opens the deactivated intake valve to relieve a negative pressure condition in the deactivated cylinder. Alternatively, the valve control system opens the deactivated exhaust valve to relieve a negative pressure condition in the deactivated cylinder.

An intake pressure sensor is provided in an intake path of a single cylinder engine and detects an intake pressure. A crank angle sensor detects a crank angle of the single cylinder engine. A sampling unit samples the intake pressure detected by the intake pressure sensor when the crank angle detected by the crank angle sensor becomes a sampling start angle. A calculation unit extracts M intake pressures of relatively small values of N intake pressures sampled by the sampling unit. The calculation unit acquires, as a bottom pressure, an average value of P intake pressures remaining after several intake pressures of relatively large values and several intake pressures of relatively small values of the M intake pressures are excluded.

An engine system for a vehicle includes an engine comprising X cylinders (X4) and Y deactivation mechanisms (X/2<Y<X), each of the Y deactivation mechanisms being configured to deactivate a different one of the X cylinders and wherein the Y deactivation mechanisms are arranged an optimal Y of the X cylinders for a defined firing order of the X cylinders. The engine system further includes a controller configured to: determine a torque request for the engine, determine a set of potential firing fractions of the engine, each firing fraction representing a particular Z of the X cylinders being deactivated (0<ZY) based on the torque request, determine an optimal firing fraction of the set of potential firing fractions, based on the optimal firing fraction, command a corresponding Z of the Y deactivation mechanisms to deactivate the determined Z of the X cylinders, and command firing of a remainder the X cylinders.

Methods of operation of liquid and gaseous multi-fuel compression ignition engines that may be operated on a gaseous fuel or a liquid fuel, or a combination of both a gaseous fuel and a liquid fuel at the same time and in some embodiments, in the same combustion event. Various embodiments are disclosed.

Methods of operation of liquid and gaseous multi-fuel compression ignition engines that may be operated on a gaseous fuel or a liquid fuel, or a combination of both a gaseous fuel and a liquid fuel at the same time and in some embodiments, in the same combustion event. Various embodiments are disclosed.

An intake pressure sensor is provided in an intake path of a single cylinder engine and detects an intake pressure. A crank angle sensor detects a crank angle of the single cylinder engine. A sampling unit samples the intake pressure detected by the intake pressure sensor when the crank angle detected by the crank angle sensor becomes a sampling start angle. A calculation unit extracts M intake pressures of relatively small values of N intake pressures sampled by the sampling unit. The calculation unit acquires, as a bottom pressure, an average value of P intake pressures remaining after several intake pressures of relatively large values and several intake pressures of relatively small values of the M intake pressures are excluded.