Abstract: An engine for use in an air hybrid vehicle comprises at least one cylinder having a piston (20) defining a variable volume working chamber (10) and intake (12, 14) and exhaust (16) valves controlling the flow of air into and out of the working chamber. The cylinder is operable in any one of at least two modes, namely a first mode in which power is generated by burning fuel in the working chamber (10), and a second mode in which the cylinder acts to compress air drawn into the working chamber (10) and to store the compressed air in an air tank (36). The engine further comprises a non-return valve (32) in an intake port leading to an intake valve (12) of the cylinder so as to define an auxiliary chamber (30) in the intake port between the intake valve (12) and the non-return valve (32). A passage (24) connecting the auxiliary chamber (30) to the air tank (36) contains a valve (34) for controlling the flow of compressed air between the auxiliary chamber (30) and the air tank (36).

Abstract: An air hybrid vehicle is described powered by an internal combustion engine (16) which may or may not be equipped with a supercharger or turbocharger (10) for boosting the engine (16). In the invention, power is taken from the vehicle to drive the engine (16) during deceleration or coasting of the vehicle. The engine (16) absorbs kinetic energy from the vehicle and uses that energy to produce boost air which is transferred and stored in a boost air storage tank (34) on board the vehicle at a storage pressure not exceeding 3 bar absolute pressure. The vehicle achieves fuel saving and high performance by boost substitution when this boost air is used to supply the engine (16) for short periods during acceleration or cruising of the vehicle without relying on any air charger, temporarily fulfilling the role of an air charger without actually driving an air charger by substituting the boost normally supplied by an air charger with an equivalent boost produced and stored during regenerative braking.

Abstract: An engine for use in an air hybrid vehicle comprises at least one cylinder having a piston (20) defining a variable volume working chamber (10) and intake (12, 14) and exhaust (16) valves controlling the flow of air into and out of the working chamber. The cylinder is operable in any one of at least two modes, namely a first mode in which power is generated by burning fuel in the working chamber (10), and a second mode in which the cylinder acts to compress air drawn into the working chamber (10) and to store the compressed air in an air tank (36). The engine further comprises a non-return valve (32) in an intake port leading to an intake valve (12) of the cylinder so as to define an auxiliary chamber (30) in the intake port between the intake valve (12) and the non-return valve (32). A passage (24) connecting the auxiliary chamber (30) to the air tank (36) contains a valve (34) for controlling the flow of compressed air between the auxiliary chamber (30) and the air tank (36).

Abstract: A method is disclosed for operating an internal combustion engine of the type having an engine cylinder with a reciprocating piston, first and second intake ports for admitting gas from an ambient air supply into the engine cylinder, first and second intake valves each arranged between a respective one of the intake ports and the engine cylinder, a non-return valve arranged in the second of the intake ports at a distance from the second intake valve and oriented to allow gas to flow only towards the engine cylinder, and a variable valve actuating system for controlling the opening and closing of at least the second intake valve. In the method of the invention, in at least one operating mode of the engine, the second intake valve is opened and closed, while the cylinder is fully isolated from the ambient air, to permit gas transfer between the cylinder and an auxiliary chamber temporarily defined by the part of the second intake port lying between the second intake valve and the non-return valve.

Abstract: An auto-ignition timing control and calibration method for use in an internal combustion engine having more than one ignition modes including the mode of compression ignition of a premixed fuel/air mixture (CAI/HCCI), wherein when the engine is operating in the CAI/HCCI mode, in order to determine a prescribed setting or combination of settings of engine operating parameters necessary to achieve a target auto-ignition timing according to a predetermined auto-ignition timing map, the associated compression temperature trajectory of the cylinder charge with time, calculated in dependence on the initial and boundary conditions of the said charge subjected to the said prescribed setting or combination of settings of the said engine operating parameters, and further in dependence on the interim heat exchange processes affecting the said charge, is used for testing and verifying that the said trajectory reaches a target temperature at a target reference timing relative to TDC of the engine, and wherein the said tar

Abstract: A multi-cylinder internal combustion engine is described in which each cylinder is capable of operating within a predetermined auto-ignition torque/speed range. Selected cylinders are disabled when the average cylinder torque lies below the auto-ignition torque/speed range so as to raise the torque of the remaining power producing cylinders and enable them to continue to operate within the auto-ignition torque/speed range.

Abstract: A multi-cylinder internal combustion engine is described in which each cylinder is capable of operating within a predetermined auto-ignition torque/speed range. Selected cylinders are disabled when the average cylinder torque lies below the auto-ignition torque/speed range so as to raise the torque of the remaining power producing cylinders and enable them to continue to operate within the auto-ignition torque/speed range.

Abstract: A lean burn engine having a lean NOx trap in the form of a matrix of narrow flow passages is described. The engine is provided with means for injecting reducing gases upstream of the NOx trap matrix (16) to purge the trap periodically. A flow straightening matrix (12) of narrow flow passages is arranged upstream of the NOx trap matrix (16) and is separated from the trap matrix (16) by a narrow chamber (14).

Abstract: An internal combustion engine includes a fuel storage tank, a fuel pump for drawing liquid fuel from the storage tank, a distillation unit for producing from the fuel drawn from the storage tank a plurality of flow streams of different volatility, and an engine management system for separately metering fuel to the engine from the flow streams. The engine management system is responsive to the rates at which the flow streams are produced by the distillation unit.

Abstract: A spark ignition gasoline internal combustion engine separates a gasoline fuel supply into a higher boiling point fraction and a lower boiling point fraction, supplies the boiling point fractions to combustion chambers of the engine, and introduces the separate boiling point fractions into the combustion chambers to produce a stratified charge with the different fractions residing in different parts of the combustion chamber. In accordance with a preferred embodiment, charge stratification under “full load” operating conditions is such that in each combustion chamber the lower boiling point fraction is ignited by a spark plug, which in turn produces a propagating flame that ignites the higher boiling point fraction concentrated in the end gas regions of the combustion chamber.

Abstract: An engine is described that has a variable valve timing system. Under low and medium load operation of the engine, the valve timing system sets an prolonged valve overlap period and fuel is injected predominantly during this prolonged overlap period either into the intake ports or directly into the combustion chambers. The effect is that the fuel is heated by the internally recirculated exhaust gases which pre-conditions the fuel to improve ignitability and combustion quality.

Abstract: A lean NOx trap in an exhaust system of a spark ignition internal combustion engine having a three-way catalyst upstream of the lean NOx trap, and the lean NOx trap connected in series along the exhaust system is heated by modulating the air to fuel ratio (AFR) of the engine cyclically at various frequencies such as 0.5 Hz, 1 Hz, 1.5 Hz, and 2 Hz, so that different portions of the lean NOx trap are heated at different times so as to completely remove sulfur from the lean NOx trap.

Abstract: A spark ignition internal combustion engine is described having a fuel supply system for separating the fuel into two or more continuous streams of fuel fractions having different octane ratings. The engine has an intake system that creates within each combustion chamber a stratified charge comprising at least two regions 113, 123 each containing a higher concentration of respective one of the fuel fractions. Each combustion chamber also has two spark plugs 114, 124 each located in a respective one of the stratified charge regions. The engine ignition system separately controls the spark timings of the spark plugs 114, 124 to vary the pattern of flame propagation through the stratified charge in the combustion chambers in dependence upon the engine operating conditions.

Abstract: The invention relates to a gasoline internal combustion spark ignition engine having a fuel fractioning system that separates the gasoline fuel by boiling point into at least two, preferably three, fractions. The different fuel fractions are separately supplied to the combustion chamber of the engine in such a manner as to achieve in each cylinder a two-zone stratification of the charge at the instant of spark when the engine is operating at low and medium loads. The two-zone stratification consists of two contiguous mixture clouds, a first of the two clouds lying in the vicinity of the spark plug and containing a higher concentration of the higher boiling point fuel fraction than the second cloud lying at a distance from the spark plug. The average composition of the fuel and the fuel-to-air ratio in the second cloud are such that the second cloud undergoes auto-ignition subsequent to the instant of spark ignition of the first cloud.

Abstract: A fuel vapour extraction system is described for an internal combustion engine (10) that is supplied with a volatile liquid fuel from a fuel storage tank (20). The engine (10) has an air intake system (12, 14, 16) and a liquid fuel injection system for dispensing fuel to mix with air to be burnt in the engine. The fuel vapour extraction system includes a volatizing chamber (30) connected to the fuel storage tank (20) by a valve (26) serving to maintain a constant liquid level of fuel in the chamber (30). A pipe (42) connected to one or more vacuum sources leads into the vapour space above the liquid level in the chamber (30) and maintains a reduced pressure in the volatizing chamber.

Abstract: An intake system for an internal combustion engine includes an intake manifold having a plenum connected to ambient air by a main throttle and branches leading from the plenum to an intake port of each cylinder. A storage pipe is connected and parallel with each of the intake manifold branches. Gases from an auxiliary supply are drawn by the intake manifold vacuum into the storage pipe and thence into the engine cylinders.

Abstract: An intake system with multiple throttles, arranged in series, is disclosed for use in a lean burn, gasoline engine. The arrangement has the facility to provide air-fuel ratios which are: leaner than stoichiometric at the light load region of the operating map, stoichiometric at the high load region of the operating map, and richer than stoichiometric at the full load region of the operating map.

Abstract: An internal combustion engine is disclosed in which, at least during part load and full load operation of the engine, fuel is injected into the combustion chamber (10) during the intake stroke while an intake valve (26) is open by means of an injector (50) positioned in an unswept part of the cylinder bore (14). The fuel spary passes through the mouth of the intake valve (26) against the flow of high velocity air leaving the intake valve (26) and enters directly into the end of the intake port (20) penetrating laterally across the through-flow cross section of the intake port (20).

Abstract: A lean burn internal combustion engine includes an intake port. The intake port supplies an intake charge to the combustion chamber and exhaust gases are discharged through an exhaust port. Fuel is supplied by a fuel injector for dispersion within the air drawn into the combustion chamber by way of the intake port, and exhaust gases from the exhaust port are recirculated to the intake port without passing through the combustion chamber through an external EGR pipe. To promote lean burn and auto-ignition at low engine load, an additional fuel supply is provided in the EGR pipe for introducing fuel to be partially oxidised within the hot EGR gases before they enter the intake port.

Abstract: An internal combustion engine is described comprising a cylinder having an intake port [14], and two manifolds [24, 34] having branches [22, 32] that are configured to supply two gas streams to the intake port [14] of each cylinder. The two streams enter the cylinder separately so as to produce a stratified charge within the engine cylinder. The first manifold [24] supplies a metered quantity of air within which the fuel to be burnt is dispersed and the second manifold [34] supplies dilution gases. A flow obstructing throttle [23] is arranged in each branch [22] of the first manifold to reduce the risk of back-filling of the branches [22] of the first manifold [24].