Methods and systems are provided for increasing engine power via partial engine enrichment and exhaust gas recirculation. In one example, a method may include enriching a first set of engine cylinders and enleaning a second, remaining set of the engine cylinders, exhaust gas from the first set and the second set producing a stoichiometric mixture at a downstream emission control device, and providing exhaust gas recirculation (EGR) to an intake passage of the engine from the first set of cylinders and not from the second set. In this way, cooling effects from the partial enrichment and the EGR enable engine air flow, and thus engine power, to be increased while an efficiency of the emission control device is maintained, thereby decreasing vehicle emissions.

A system and method for providing torque-assist to a rotary shaft of an internal combustion engine control an electric machine in response to operation of an exhaust gas recirculation (EGR) valve to assist the rotation of the rotary shaft. The system and method facilitate periodic operation of the EGR valve to purge condensation without objectionable torque reduction when the engine is operating near full load.

A vehicle engine automatic control device has a brake operation amount detecting unit that detects an amount of brake operation by a driver, an engine stopping/re-starting unit that, during coast drive, stops an engine based on the amount of brake operation that is detected, and, after the engine stops, re-starts the engine when the amount of brake operation that is detected falls below a first threshold, and a first threshold setting unit that sets the first threshold smaller as vehicle speed becomes lower.

A driving force control system according to an embodiment of the present invention includes: an absolute bank angle detector configured to detect an absolute bank angle that is the absolute value of a vehicle's bank angle; a calculation circuit configured to calculate a relative bank angle that is the vehicle's relative angle with respect to a maximum absolute bank angle that is the maximum value of the absolute bank angle; and a controller configured to control driving force based on the relative bank angle.

Methods and systems are presented for assessing the presence or absence of engine torque deviation which may indicate air-fuel ratio imbalance between engine cylinders. In one example, the method may include assessing the presence or absence of engine torque variation based on engine torque deviation from a desired engine torque during a deceleration fuel shut-off event.

A vehicle and method for controlling a vehicle having a variable displacement engine with an auxiliary machine connected directly to the engine crankshaft and to an energy storage device includes switching from a cylinder disablement (VDE) mode to a normal mode when the torque demand and engine speed lie outside an outer range defined by a first threshold (T.sub.out), and switching from the normal mode to the VDE mode when the torque demand and engine speed lie within an inner range, which lies within the outer range and defined by a second threshold (T.sub.in). When operating in a band between the two thresholds, the auxiliary machine draws energy from the energy storage device and supplements the output torque from the engine if operating in the VDE mode, and derives torque from the engine crankshaft to recharge the energy storage device if operating in the normal mode.

The engine control device comprises a basic target torque-deciding part for deciding a basic target torque based on a driving state of a vehicle, a torque reduction amount-deciding part for deciding a torque reduction amount based on a steering wheel operation state, an TCM for deciding a torque-down demand amount, based on a driving state of the vehicle other than the steering wheel operation state, and a final target torque-deciding part for deciding a final target torque, based on the decided basic target torque, the decided torque reduction amount and the decided torque-down demand amount, wherein the final target torque-deciding part is operable, when there is a torque-down demand, to restrict a change in the final target torque corresponding to a change in the torque reduction amount.

In a constant-speed traveling mode or a follow-up traveling mode, reduction of fuel consumption and improvement of drivability are both achieved. An ECU 110 has an ISG connected to an engine and a battery connected to the ISG. The ECU 110 has an ISG control unit 606 that performs control for supplying power to the ISG from the battery to rotationally drive the ISG, or to drive the ISG to generate power for charging the battery. In one cycle of a traveling mode until completion of deceleration traveling after acceleration traveling is started so as to achieve a target vehicle speed, the ISG control unit 606 drives the ISG such that a remaining charge amount of the battery falls within a set range at completion of the deceleration traveling, and a traveling acceleration/deceleration falls within a predetermined requested acceleration/deceleration.

For an engine that draws a complicated torque trajectory, it has been taken a lot of time to adapt a time constant for calculation of estimated torque. Therefore, an ECU 102 includes a target torque calculation unit 203 that calculates target torque of an engine for which torque-based engine control is performed using estimated torque, and an estimated torque calculation unit 210 that calculates the estimated torque by calculating a primary delay coefficient 304 equivalent to a time constant calculated for each control cycle based on a change in an actual intake air amount with respect to a target intake air amount of air sucked into the engine and performing primary delay processing on the target torque using the primary delay coefficient 304.

A system includes an electronic fuel injection system of an engine, the electronic fuel injection system including an electronic governor control unit for controlling various functions of the engine.