摘要:
Nanopatterned surfaces which provide for improved cell growth including improved stem cell differentiation. The patterned surfaces can comprise an array of fields of biologically active moieties and can be controlled by parameters which include the pitch between the fields and the size of the fields. Nanopatterning can be carried out with use of dip pen nanolithographic printing, microcontact printing, and nanoimprint lithography.
摘要:
An air fuel ratio control system for an internal combustion engine having an electronic engine control module and an upstream and a downstream exhaust gas oxygen sensor positioned in the engine exhaust gas stream. A first feedback loop includes the upstream EGO sensor and an air fuel bias table. A second feedback loop includes a downstream EGO sensor and a trim signal to change the stored values in the air fuel bias table.
摘要:
An exhaust gas oxygen sensor is used to control the air/fuel ratio of an internal combustion engine in combination with an electronic engine control. The exhaust gas oxygen sensor is positioned in the exhaust stream flow from the engine. The electronic engine control utilizes different air/fuel ratio feedback strategies depending upon whether the signal output from the exhaust gas oxygen sensor is saturated indicating a rich air/fuel ratio, saturated indicating a lean air/fuel ratio or operating in a linear region.
摘要:
A proportional plus integral feedback control system is responsive to a two-state, filtered output signal from an exhaust gas oxygen sensor. The sensor's output is offset from stoichiometric switching by the presence of alcohol in the fuel blend. A correcting bias term is calculated and the average value of the feedback variable is appropriately biased by selection of the proportional plus integral terms.
摘要:
A method and system are provided for modifying a control signal of a fuel injector of a fuel delivery system wherein at least one shut-down temperature signal representing the temperature of an internal combustion engine is utilized together with other input signals to calculate a net amount of heat transferred to the fuel delivery system. The signals are utilized to calculate a correction factor, which correction is used to modify the control signal for the fuel injector. Preferably, two shut-down temperature signals are utilized, an engine coolant shut-down temperature signal and an air charge shut-down temperature signal to calculate the net amount of heat transferred. The modified control signal provides accurate control of the fuel injector by compensating for the increased volatility of the heated liquid fuel. When the liquid fuel is a blended fuel such as gasoline/methanol, a blend signal is generated based on the relative amount of one of the liquid fuels in the blended fuel and the step of calculating the correction factor is also based on the blend signal. The method and system provide improved hot start fuel control.
摘要:
An air fuel ratio control system for an internal combustion engine having an electronic engine control module and an upstream and downstream exhaust gas oxygen sensor positioned in the engine exhaust gas stream. A first feedback loop includes the upstream EGO sensor. A second feedback loop includes a downstream EGO sensor and a trim bias signal to bias stored values provided from an air/fuel bias table. Such a biased signal is applied to an air fuel feedback controller which provides a feedback air fuel control signal to be applied to an open loop fuel controller.
摘要:
An electronic engine control system for use with differing fuel types, such as gasoline, methanol and mixtures of the two, controls engine operating parameters such as the fuel/air ratio and ignition timing in response to fuel-type indications generated by a fuel type sensor positioned on the fuel line. Changes in the fuel type passing the sensor result in variations in the engine control signals which are effective after a variable delay period elapses. The duration of the variable delay period is altered in response to changes in fuel pump voltage and fuel temperature to form a better estimate of the transport delay experienced by the fuel as it passed from the fuel-type sensor to the engine's fuel intake. A microcontroller delays the control signal changes by retrieving a count value from a two-dimensional lookup table indexed by values reflecting pump voltage and fuel temperature. The count value is placed in a countdown timer which is decremented to zero for establishing a subinterval, at the conclusion of which the current fuel type signal is pushed into a FIFO stack as the oldest stored fuel type value is popped from the stack and supplied to the engine controller. In this way, the stack operates as a variable duration delay device which is updated at the end of subintervals each having a duration dependent upon the estimated fuel transport delay.
摘要:
An air/fuel control system for use with an internal combustion engine which is adapted to burn fuels having different combustion characteristics. The control system compensates for errors in the fuel-type signal produced by a sensor and provides a failure mode of operation when the sensor fails. A closed-loop air/fuel mixture controller responds to sensed exhaust oxygen levels to maintain combustion near stoichiometry. When the errors from the fuel type sensor predominate, at high engine speed and load, a selected one of two fuel-type variables, is adaptively modified. The first variable is modified in response to the control system's inability to achieve stoichiometry during high speed/high load operation, a condition which causes the first variable to correct the fuel type signal from the sensor. The second variable assumes control when the first variable is unable to achieve stoichiometry, indicating sensor failure, and is updated in accordance with a more vigorous strategy. The second variable is modified regardless of engine speed and load, and closed-loop adaptive processing is forced even when the exhaust level signal no longer switches. The limits on the exhaust level signal are relaxed to allow it to grow to larger magnitudes, and processing which is not needed during failure mode is discontinued to allow adaptive processing to proceed more rapidly.
摘要:
An air/fuel control system for use with an internal combustion engine which is adapted to burn fuels having different combustion characteristics. The control system compensates for errors in the fuel-type signal produced by a sensor. A closed-loop air/fuel mixture controller responds to sensed exhaust oxygen levels to maintain combustion near stoichiometry. When the errors from the fuel type sensor predominate, at high engine speed and load, a fuel-type variable, initially obtained from the sensor, is adaptively modified. The error compensation scheme thus adapts to changing fuels, fuel sensor errors, and differing engine operating characteristics to provide better fuel control and improved performance.