A miller cycle engine according to the present disclosure includes: a variable valve operating device configured to continuously change the closing timing of an intake valve; a throttle valve arranged in an intake air passage; and a control device configured to execute an early closing miller cycle operation mode to control the variable valve operating device such that the intake valve closes at an intake bottom dead center or earlier. The control device is configured to: execute a late closing mode (e.g., decompression mode) to retard the closing timing relative to the intake bottom dead center at the time of engine start-up; and execute, where the pressure in the intake air passage has decreased to a first threshold value or lower first after the engine start-up, a mode switching processing to switch from the late closing mode to the early closing miller cycle operation mode.

Systems and methods for operating an internal combustion engine that may be automatically stopped and started are described. In one example, an engine is rotated in a reverse direction after an engine stop so that a belt integrated starter/generator may rotate the engine in a forward direction and utilize the inertia of the engine to rotate trough top-dead-center compression stroke, thereby starting the engine.

An apparatus for starting engine of mild hybrid electric vehicle according to an exemplary embodiment of the present disclosure may include: an ignition switch including a plurality of contact points; A gradient detector configured for detecting a road gradient of a road on which the vehicle is located; a state of charge (SOC) detector configured for detecting an SOC of a high voltage battery; a mild hybrid starter & generator (MHSG) including a stator and a rotor disposed inside the stator, and starting the engine or generating electricity by an output of the engine; a starter which is able to start the engine independently from the MHSG; an MHSG wheel rotating integrally with the rotor; an MHSG position detector configured for detecting a position of the MHSG; and a controller configured for determining a top dead center (TDC) of a predetermined cylinder based on a signal of the MHSG position detector.

A drive control section automatically stops an engine by stopping fuel injection and by closing a throttle valve that adjusts the amount of intake air when a predetermined specified condition is satisfied. A stopping-angle detection section detects a crank angle when the engine is automatically stopped as a stopping angle. The drive control section cranks the engine before an in-cylinder negative pressure period, in which pressure in a cylinder of the engine is negative pressure, elapses after starting to automatically stop the engine if the stopping angle is outside an allowable crank-angle range in which it is possible to restart the engine by cranking the engine by the motor generator.

A prime mover for a lightweight vehicle comprising an internal combustion engine, a starter motor integrally integrated with the internal combustion engine, and a housing for the prime mover. The prime mover additionally comprises a Hall Effect sensor and an prime mover control module structured and operable to communicate with the Hall Effect sensor, determine when operation of the internal combustion engine should cease, and upon the determination that operation of the internal combustion engine should cease, utilize the communication from the Hall Effect sensor to stop the internal combustion engine such that a piston of the internal combustion engine is positioned at between 15 and 25 after bottom-dead-center.

A method of controlled stopping an internal combustion engine having a stop-start mode and starter assembly includes detecting when the stop-start mode is active. The method also includes monitoring current rotational speed and position of the engine. The method additionally includes determining when the current rotational position is within a predetermined range of a target stop rotational position and the current rotational speed is less than a threshold rotational speed, and afterward energizing the starter assembly to engage the engine. The method also includes establishing a time delay following energizing the starter assembly to confirm engagement of the starter assembly with the engine. Furthermore, the method includes applying a torque by the starter assembly to stop the engine at the target stop position. A vehicle powertrain employing the engine equipped with the stop-start mode, the starter assembly, and an electronic controller configured to execute the method is also provided.

A prime mover for a lightweight vehicle comprising an internal combustion engine, a starter motor integrally integrated with the internal combustion engine, and a housing for the prime mover. The prime mover additionally comprises a Hall Effect sensor and an prime mover control module structured and operable to communicate with the Hall Effect sensor, determine when operation of the internal combustion engine should cease, and upon the determination that operation of the internal combustion engine should cease, utilize the communication from the Hall Effect sensor to stop the internal combustion engine such that a piston of the internal combustion engine is positioned at between 15 and 25 after bottom-dead-center.

A restart control system includes a rotational angle estimation unit that estimates a rotating electrical machine's rotational angle in a state wherein an internal-combustion engine's rotational speed detected by a rotational speed detection unit is higher than an estimation threshold and configured not to estimate rotating electrical machine's rotational angle in a state wherein internal-combustion engine's rotational speed is lower than estimation threshold; a rotating electrical machine control unit increases internal-combustion engine's rotational speed by rotating electrical machine under condition where predetermined restart conditions are satisfied and rotating electrical machine's rotational angle is estimated by rotational angle estimation unit, thereby restarting the internal-combustion engine; and a starter motor control unit starts driving of a starter motor under a condition where predetermined restart conditions are satisfied and internal-combustion engine's rotational speed falls below a predetermined rotational speed set lower than estimation threshold, thereby increasing internal-combustion engine's rotational speed to estimation threshold.

In the start control, the first and second discharge actions of the ignition apparatuses are controlled. The first discharge action is performed to ignite the mixed gas in the multiple cylinders. The second discharge action is performed to generate the ozone. The first discharge action is performed immediately after the start of the cranking. The first discharge action is performed in the cylinders which belongs to the first and second cylinder groups. The second discharge action is performed before the start of the cranking. The second discharge action is performed in at least one cylinder which belongs to the second cylinder group. The multiple cylinders belong to the first or second cylinder group. The multiple cylinders are classified into the first or second cylinder group based on the crank angle section S.sub.CA set for each cylinder.

Systems and methods for operating an engine that may be frequently stopped and restarted are described. In one example, an engine is rotated in small crankshaft angle increments and stopped after the engine is rotated through a predetermined actual total number of crankshaft degrees so that the engine position does not change when the engine reaches a desired position.