Engine systems which are safer and have reduced risk of fire are desirable in a wide range of equipment markets. The present engine systems utilize sensors and control systems which reduce the probability of fire or spark exiting the exhaust system. The sensors may monitor a wide range of conditions within the exhaust system to alter the operating parameters of the engine to prevent ignition of objects adjacent the engine system during use. By altering operation of the engine, conditions such as exhaust temperature or unburned fuel can be controlled to minimize risk of undesired ignition.

An internal combustion engine (1) operating in cycles, having: a plurality of piston-cylinder units (2), wherein each piston-cylinder unit (2) of the plurality of piston-cylinder units (2) is assigned an ignition device (3) which can be controlled regarding activation and selection of an ignition timing by an engine control (4), wherein a piston-cylinder unit (2), when the ignition device (3) is activated, produces a power by combustion of a gas-air mixture, which can be transmitted as a torque to a crankshaft (5) of the internal combustion engine (1) an intake stroke (6) and an exhaust stroke (7), each coupled to the plurality of piston-cylinder units (2) a supply device (8) for supplying a gas-air mixture under a boost pressure to the intake stroke (6) a signal detection device (9) for acquiring at least one signal which represents a power demand on the internal combustion engine (1) or from which a power demand on the internal combustion engine (1) can be calculated an engine control (4) for actuating actuators of the internal combustion engine (1), wherein the at least one signal can be fed to the engine control (4), and the engine control (4) is configured in a first operating mode to leave as many ignition devices (8) deactivated per cycle of the internal combustion engine in dependence on the currently present power demand, that the power of those piston-cylinder units (2), the ignition devices (8) of which are activated, results in a torque of the crankshaft (5) of the internal combustion engine (1) adapted to the currently present power demand
wherein the engine control (4) is configured to, in a second operating mode, for reducing a risk of deflagration due to unburned gas-air mixture present in the exhaust stroke (7) after a first number (N.sub.1) of cycles of the internal combustion engine (1), for a second number (N.sub.2) of cycles of the internal combustion engine (1), to have more piston-cylinder units (2) produce power per cycle by activating the assigned ignition devices (8) than would be required for the currently present power demand after the second number (N.sub.2) of cycles of the internal combustion engine (1), for a third number (N.sub.3) of cycles of the internal combustion engine (1), in dependence on a currently present power demand per cycle of the internal combustion engine (1), to have so many piston-cylinder units (2) produce power by activation of the assigned ignit

A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The recipe is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.

A system and method for transitioning a firing fraction of a variable displacement internal combustion engine when generating a desired torque output. During and following the transition to the second firing fraction, a combustion recipe is ascertained and used operating the cylinders of the variable displacement internal combustion engine to generate the desired torque output. The recipe is preferably optimized for the engine operating at the second firing fraction, at least relative to the previous charge of the previous combustion recipe used with the first firing fraction.

A method of determining a condition of a component (e.g., valves) of an engine having a manifold air pressure sensor during a cold test includes providing pressurized air to an intake of the engine. The method includes rotating a crankshaft of the engine. The method includes measuring pressures with the manifold air pressure sensor as a function of crankshaft rotational position. The method includes comparing the pressures with a predetermined baseline. The method includes indicating a condition of the component based on the comparison of the pressures with the baseline.

A method of determining a condition of a component (e.g., valves) of an engine having a manifold air pressure sensor during a cold test includes providing pressurized air to an intake of the engine. The method includes rotating a crankshaft of the engine. The method includes measuring pressures with the manifold air pressure sensor as a function of crankshaft rotational position. The method includes comparing the pressures with a predetermined baseline. The method includes indicating a condition of the component based on the comparison of the pressures with the baseline.

A navigation system is described for a vehicle equipped with an autonomous driving system. The navigation system includes a human-machine interface with a display and a user control, and an electronic controller. The controller is configured to calculate a plurality of travel routes from a determined starting point to a defined destination point. The controller determines which portions of each travel route will utilized automated driving operation and which portions will utilized manual driving operation. Based on an input received from the user control, the controller defines an automatic-manual driving preference ratio indicating a driver preference for an amount of manual driving operation relative to an amount of automatic driving operation. The controller automatically selects a route from the plurality of travel routes that most closely matches the defined automatic-manual driving preference ratio and outputs the selected route on the display.

A variety of methods and arrangements are described for controlling transitions between firing fractions during skip fire and potentially variable displacement operation of an engine. In general, cam first transition strategies are described in which the cam phase is changed to, or close to a target cam phase before a corresponding firing fraction change is implemented. When the cam phase change associated with a desired firing fraction change is relatively large, the firing fraction change is divided into a series of two or more firing fraction change steps—with each step using a cam first transition approach. A number of intermediate target selection schemes are described as well.

A variety of methods and arrangements are described for controlling transitions between firing fractions during skip fire and potentially variable displacement operation of an engine. In general, cam first transition strategies are described in which the cam phase is changed to, or close to a target cam phase before a corresponding firing fraction change is implemented. When the cam phase change associated with a desired firing fraction change is relatively large, the firing fraction change is divided into a series of two or more firing fraction change steps—with each step using a cam first transition approach. A number of intermediate target selection schemes are described as well.

Methods, devices, estimators, controllers and algorithms are described for estimating working chamber air charge during engine operations. The described approaches and devices are well suited for use in dynamic firing level modulation controlled engines. Manifold pressure is estimated for a time corresponding to an induction event associated with a selected working cycle. The manifold pressure estimate accounts for impacts from one or more intervening potential induction events that will occur between the time that the manifold pressure is estimated and the time that the induction event associated with the selected working cycle occurs. The estimated manifold pressure is used in the estimation of the air charge for the selected working cycle. The described approach may be used to individually calculate the air charge for each induction event at any time that the engine is operating in a mode that can benefit from the individual cylinder air charge estimations.