Gm Global Technolgoy Operations, Inc.

Douglas E Trombley

Kenneth J Buslepp

William Conrad Albertson

Paul E Reinke

Aparicio J Gomez

Steven D Stiles

Ljubisa M Mladenovic

Jeffrey James Allen

Mark G Kosowski

John M Gunselman

Cathy C Lillie

Dennis W Montville

Ronald J Sikarskie

Marcel R Wancket

Yoshiki Torii

Noboru Takahashi

Dietmar Mueller

Kenneth G Macklem

Thomas Wagner

Nils Sandmann

Toshio Ichimasa

A method of diagnosing a fuel injector of an engine system as contaminated is provided. The method comprises: recording a first fuel injection quantity; commanding a fuel rail pressure high; recording a second fuel injection quantity while the fuel rail pressure is high; and diagnosing the fuel injector as contaminated if the first fuel injection quantity is greater than the second fuel injection quantity.

Method to detect a contaminated fuel injector

An engine control system that regulates operation of an engine includes an intake valve that regulates air intake into a cylinder of the engine and an exhaust valve that regulates exhaust from the cylinder. A control module determines a cylinder volume at intake valve closure and a cylinder volume at intake valve opening and calculates an intake pumping torque based on the cylinder volume at intake valve closure and the cylinder volume at intake valve opening. The control module determines a cylinder volume at exhaust valve closure and a cylinder volume at exhaust valve opening and calculates an exhaust pumping torque based on the cylinder volume at exhaust valve closure and the cylinder volume at exhaust valve opening. The control module calculates a net pumping torque based on the intake pumping torque and the exhaust pumping torque and regulates engine operation based on the net pumping torque.

Dynamic engine pumping work estimation algorithm

A control system that determines a mass air flow through a throttle of an internal combustion engine (ICE) having an intake manifold includes a calculator that calculates an estimated mass air flow based on a throttle position and an adjustment module that determines an adjustment value. The adjustment value is based on the estimated mass air flow, an estimated manifold absolute pressure and a measured manifold absolute pressure. A multiplier multiplies the estimated mass air flow by the adjustment value to determine the mass air flow.

Mass air flow estimation based on manifold absolute pressure

Air/fuel ratio control compensation is applied to an internal combustion engine having pneumatic fuel injection, wherein an engine operating condition is determined and appropriate compensation provided to the fuel command when an operating condition is sensed in which a significant fuel residue remains in the pneumatic injector after the end of an injection period.

Transient fueling compensation

Engine inlet air/fuel ratio compensation is applied to an internal combustion engine having pneumatic fuel injection, wherein the difference between a value proportional to inlet air pressure and a value proportional to inlet fuel pressure is monitored and a commanded fuel or air quantity adjusted as a predetermined function of the difference.

Internal combustion engine air/fuel ratio compensation

An idle speed regulating system is described for an internal combustion engine operating according to a fuel based control strategy, wherein the amount of fuel delivered the engine is determined directly as a function of the demand for engine output power and the amount of air supplied to the engine is controlled as a function of the quantity of delivered fuel. The system senses the actual idling rotational speed of the engine, derives a desired idling speed for the engine, and reduces the difference between the desired and actual idling speeds by adjusting the flow rate of the quantity of fuel delivered to the engine as a function of the difference between the desired and actual idling speeds. More specifically, the rate of fuel flow is adjusted in accordance with the sum of an open-loop feedforward value, a closed-loop feedback value, and preferably an adaptive learning correction value.

Engine idle speed control based upon fuel mass flow rate adjustment

A method is described for controlling the injection of fuel in a direct injected, multi-cylinder internal combustion engine, to smooth transients in engine output torque associated with a deceleration fuel cut-off mode of engine operation. This is accomplished by detecting engine operating conditions that call for the initiation of a transition associated with the decelaration fuel cut-off engine operating mode. In response to the detected operating conditions, a transitional period is initiated, during which the injection of fuel into a varying portion of engine cylinders is then interrupted. When the transitional period is associated with entry into the deceleration fuel cut-off mode, the injection of fuel to a progressively increasing number of cylinders is interrupted. When the transitional period is associated with recovery from the deceleration fuel cut-off mode, the injection of fuel to a progressively decreasing number of engine cylinders is interrupted. The rate of entry into the fuel cut-off mode is preferably fixed, while the rate of receovery is determined in accordance with the position of an engine control element for adjusting the amount of torque developed at the engine output. Alternatively, the rate of recovery may be determined by the maximum rate of positional change of the engine control element.

Control of engine fuel injection during transitional periods associated

A method is described for increasing engine braking, when a crankcase scavenged two-stroke engine is operated in a deceleration fuel cut-off mode. In response to the detection of operating conditions indicating engine operation in the deceleration fuel cut-off mode, the quantity of air inducted into the engine is decreased, for a predetermined period of time. After this period of time elapses, the quantity of air inducted into the engine is then increased. This is preferably accomplished by regulating the degree of opening of a throttle valve disposed within the engine air intake system. The initial closing of the throttle valve restricts air flow through the engine for a predetermined time, to maintain efficient catalyst operating temperatures in the engine exhaust system. During extended operation in the deceleration fuel cut-off mode, the throttle valve is opened, after the lapse of the predetermined time, to increase the quantity of air inducted by the engine. This results in increased engine braking, due to the additional work that must be performed in compressing the larger quantity of inducted air.

Method for controlling a crankcase scavenged two-stroke engine during

An adaptive learning control method is described for regulating the quantity of air inducted into a fuel injected internal combustion engine to achieve a desired air-fuel ratio, where the amount of fuel supplied to each engine cylinder is determined directly as a function of operator demand for engine output. The rotational speed of the engine is sensed, and indication are derived for the actual mass of air inducted into each engine cylinder and for a desired mass of air for each engine cylinder. For the region in which the engine is operating, open-loop and closed-loop values are determined for controlling engine air flow. A previously stored learning correction value corresponding to the engine operating region is obtained, and the quantity of air flowing to the engine is adjusted in accordance with the sum of the open-loop value, the closed-loop value, and the learning correction value. The learning correction value is periodically updated as a function of the difference between the indicated actual and desired mass of air for each engine cylinder, when the engine continuously operates in the region and a predetermined time has elapsed since the engine first began continuous operation in the region.

Adaptive learning control for engine intake air flow

A method and means are described for determining the average backpressure at a cylinder exhaust port in a crankcase scavenged two-cycle engine. The exhaust backpressure is determined by averaging the pressure of air within a crankcase chamber associated with the cylinder, during a portion of the engine operating cycle when the cylinder inlet and exhaust ports are simultaneously open. The overlap interval in port openings creates a channel for airflow between the crankcase chamber and the cylinder exhaust port, and except for an initial portion of the interval assocated with the pressure equalization between the cylinder and its crankcase chamber, the crankcase pressure substantially equals the backpressure appearing at the cylinder exhaust port. In the preferred embodiment of the invention, a pressure sensor is disposed within the crankcase chamber to sample air pressure at specified engine rotational positions during the overlap interval. These samples are then numerically averaged to obtain the average exhaust backpressure, which is used for compensating the amount of air inducted per cylinder per engine cycle to determined the amount of air per cylinder trapped and available for combustion within the engine. The control of the engine is thereby automatically corrected to account for changes in the engine exhaust system, the altitude of engine operation, and local barometric pressure.

Method and means for determining exhaust backpressure in a crankcase

A method and apparatus for improving the output torque response of a crankase scavenged, two-stroke engine to a change in throttle position by adjusting the conventional timing of cylinder fuel injection as a function of the position of the throttle and the time rate of change in the throttle position. Preferably, throttle position is measured with a potentiometer connected to the engine air intake throttle, and then filtered with a filter having a first order lag characteristic. Injection timing is advanced based upon a first predetermined schedule as a function of the measured throttle position. The difference between the measured and filtered throttle positions represents an indication of the time rate of change of throttle position and is employed to advance or retard timing in accordance with the second predetermined schedule, depending upon whether the difference is positive or negative, respectively. As a result, a substantially linear relationship is established between the output torque of the engine and the position of the throttle over its entire range of movement, and the amount of time required for the engine to respond to abrupt changes in throttle is reduced.

Fuel injection timing control for a crankcase scavenged two-stroke engine

A method and apparatus for controlling the idling rotational speed of a direct fuel injected, crankcase scavenged, two-stroke engine are disclosed. This is accomplished by regulating the timing of engine fuel injection within the rotational cycle of the engine. If the engine idling speed is outside a predetermined range of speeds, containing a target idling speed, the timing of fuel injection is advanced within the rotational cycle of the engine to increse idling speed, or retarded to decrease idling speed. The value by which fuel injection timing is advanced or retarded is determined by the difference between the actual idling speed and the target idling speed. The target idling speed is made a function of engine operation temperature to assure that a cold engine will idle properly when first started. After fuel injection timing is changed, a predetermined period of time is waited before repeating the idle control steps, to allow engine speed to stabilize. The method also provides for advancing fuel injection timing by a relatively large amount in the event that the idling speed falls below a predetermined stalling speed. The stalling speed is made to depend upon engine operating temperature by equating it to the target idling speed reduced by a fixed quantity.

Idle control system for a crankcase scavenged two-stroke engine

A method and means are described for determining the mass of air available for combustion within a cylinder of a crankcase scavenged two-cycle engine, without the use of a mass-air flow sensor. This is achieved by estimating the mass of air under compression within a crankcase chamber, prior to its transfer to a cylinder combustion chamber during the engine operating cycle. The estimate for air mass is based upon the polytropic behavior of a portion of the crankcase compression process, and the pressure, volume and temperature of the air at two predetermined engine rotational positions during the polytropic phase of compression. The volume of the air within the crankcase chamber is determined as a function of engine rotational angle, with crankcase air temperature being derived as a function of intake air temperature. Air pressure during the polytropic phase of compression is sensed with a pressure sensor disposed within the crankcase chamber. The estimate for air mass is corrected to account for air leakage and imperfect transference of the air between the crankcase and combustion chambers.

Method and means for determining air mass in a crankcase scavenged

A combustion control for an internal combustion engine adjusts ignition timing and A/F ratio to even the torque pulses of the individual cylinders as well as adjust LPP toward a desired value (DLPP). The crank angle (LPP) and magnitude (MPP) of peak combustion pressure is sensed for each cylinder and the average MPP for all cylinders (AMPP) is derived. Ignition timing is trimmed, within a first limit, in response to LPP to attempt to maintain DLPP. MPP is compared with AMPP and, if it is too low, ignition timing is trimmed in the advance direction to a second limit, which is preferably larger than the first. Only if the MPP trim of ignition timing is at maximum advance, or if MPP is too high, is A/F ratio adjusted, with MPP trim of ignition reset to zero. Thus, fuel consumption is minimized as the cylinder torques are balanced.

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Grosse Pointe, MI, United States of America

Douglas E Trombley