1986 results about "Cylinder pressure" patented technology

A premixed charge compression ignition engine, and a control system, is provided which effectively initiates combustion by compression ignition and maintains stable combustion while achieving extremely low nitrous oxide emissions, good overall efficiency and acceptable combustion noise and cylinder pressures. The present engine and control system effectively controls the combustion history, that is, the time at which combustion occurs, the rate of combustion, the duration of combustion and/or the completeness of combustion, by controlling the operation of certain control variables providing temperature control, pressure control, control of the mixture's autoignition properties and equivalence ratio control. The combustion control system provides active feedback control of the combustion event and includes a sensor, e.g. pressure sensor, for detecting an engine operating condition indicative of the combustion history, e.g. the start of combustion, and generating an associated engine operating condition signal. A processor receives the signal and generates control signals based on the engine operating condition signal for controlling various engine components to control the temperature, pressure, equivalence ratio and/or autoignition properties so as to variably control the combustion history of future combustion events to achieve stable, low emission combustion in each cylinder and combustion balancing between the cylinders.

In a control apparatus for controlling a variable valve actuation system employed in an internal combustion engine, engine/vehicle sensors are provided to detect at least a cylinder pressure in an engine cylinder for monitoring a change of state in combustion, arising from fluctuations in states/characteristics of air-fuel mixture such as a change in fuel property. Also provided is a control system that controls the variable valve actuation system responsively to a manipulated variable modified based on the cylinder pressure reflecting the change of state in combustion by a model of combustion.

A system and method are described for reducing engine vibration during cylinder deactivation in selected operating conditions. The method utilizes open valve deactivation to better match the cylinder pressure of deactivated cylinders to combusting cylinders. This mode is utilized, along with cylinder closed valve cylinder deactivation, to improve overall fuel economy, while at the same time reducing vibration felt by the vehicle driver.

Cylinders of a diesel engine 1 are provided with cylinder pressure sensors 29a to 29d for detecting combustion chamber pressures. An electronic control unit (ECU) 20 of the engine selects optimum combustion parameters in accordance with a fuel injection mode of fuel injectors 10a to 10d of the engine and a combustion mode determined by the amount of EGR gas supplied from the EGR valve 35 from among a plurality of types of combustion parameters expressing the combustion state of the engine calculated based on the cylinder pressure sensor output and feedback controls the fuel injection amount and fuel injection timing so that the values of the combustion parameters match target values determined in accordance with the engine operating conditions. Due to this, the engine combustion state is controlled to the optimum state at all times regardless of the fuel injection mode or combustion mode.

What is disclosed is a micro-pilot injection ignition type gas engine, whereby an air fuel ratio control in starting the engine is executed with enhanced precision, by means of introducing skip-firing intermittent operations which reflect the engine operation conditions, while an idling time span can be shortened or omitted.

The engine includes: a gas valve that opens and closes a fuel-gas passage in front of each cylinder, so as to arbitrarily control the throat area as well as the opening-closing time span of the gas valve; an engine speed detecting unit to detect the engine speed; a combustion diagnosis unit to detect an engine combustion state through a cylinder pressure distribution along elapsed time, as to each cylinder; an opening-closing control unit as to the gas valve, so as to control the intermittent opening-closing of the gas valve according to the levels of the detected engine speed as well as the cylinder pressure distribution; whereby, in starting the engine, the intermittent opening-closing of the gas-valve enables at least one skip-firing mode that brings an enhanced fuel-supply pressure-pulsation with which a relatively large amount of fuel-gas is supplied per engine cycle with firing so that the air fuel-gas ratio of each cylinder reaches a prescribed target value.

When a maximum value of vibration intensity (maximum vibration intensity) (Vmax) acquired from a vibration sensor (33) in a low engine speed/high engine load (operating region (R)) is equal to or greater than a given threshold value (X), a spark timing of a spark plug (16) is shifted from a point set in a normal state on a retard side with respect to a compression top dead center, farther toward the retard side. Then, when a maximum vibration intensity (Vmax2) acquired after the spark timing retard is greater than a maximum vibration intensity (Vmax1) acquired before the spark timing retard, it is determined that preignition occurs. This technique makes it possible to reliably detect preignition using the vibration sensor, while distinguishing the preignition from knocking. An in-cylinder pressure sensor for detecting an in-cylinder pressure of an engine may be used to determine the presence or absence of the preignition, in the same manner.

A method of operating an internal combustion engine having a combustion chamber with a piston and a spark plug, comprising during a first mode, bringing the temperature of the combustion chamber to auto-ignition temperature by adjusting engine operating conditions and producing auto-ignition in said combustion chamber without requiring spark from said spark plug; and during a second mode, bringing the temperature of the combustion chamber close to auto-ignition temperature by adjusting engine operating conditions, forming a small cloud of stratified air-fuel mixture near said spark plug, igniting said fuel cloud by a spark form said spark plug, and then causing cylinder pressure to rise, thereby producing auto-ignition at other sites in said combustion chamber wherein said first mode is implemented in a first operating range and said second mode is implemented only in a second operating range where engine speed and load are lower than said first operating range.

The invention relates to an urban tram braking system. The system comprises a braking instruction generation system, a braking control system and an anti-skid system, wherein the braking instruction generation system comprises a braking electronic control unit (BECU) and a braking control unit (BCU) and sends a braking instruction to the BECU; the BECU calculates required braking force according to the braking instruction and loading force detected by a loading pressure sensor and provides the braking force for a traction control unit; the traction control unit feeds a dynamic braking force signal back to the BECU; the BECU calculates air braking force which is needed to be supplemented and controls the BCU to generate braking cylinder pressure so as to realize braking control; the braking instruction generation system is provided with a driver controller, an emergency braking switch and a logic control unit connected with the emergency braking switch; the anti-skid system comprises a speed sensor arranged on a wheel axle and an anti-skid exhaust valve arranged on a braking cylinder pipe; the speed sensor detects a speed signal and transmits the speed signal to the BECU; and the BECU controls the action of the anti-skid exhaust valve according to the speed signal.

To enable operation of an internal combustion engine even without the signals of a phase sensor while nonetheless enabling an emergency driving function in the case of a disturbance of a crankshaft signal acquired by a crankshaft sensor, a cylinder pressure is acquired using a cylinder pressure sensor and it is checked whether the cylinder pressure reaches a prespecifiable threshold value. When the threshold value is reached or exceeded, an angular position associated with the threshold value is inferred. The angular position is then made available for an operation of the internal combustion engine.

A skid steer vehicle has a suspension that includes a control arm pivotally coupled to the vehicle chassis that is supported by a hydraulic cylinder connected to an accumulator to provide springing. A hydraulic circuit coupled to the cylinder and accumulator permit the operator to raise and lower the chassis, to lock the suspension while the vehicle is loaded, and to automatically charge or discharge the accumulator to match the cylinder pressure during loading and unloading. In this manner, when the suspension is unlocked after loading, the vehicle chassis neither rises nor falls.

An engine intake valve has a threaded blind bore opening from its top surface facing the engine cylinder. A pressure sensor has a body portion whose exterior is threaded and is configured in size and shape to be completely received within and retained in the blind bore. The pressure sensor is configured to generate a pressure signal indicative of the cylinder pressure.

The invention discloses a constant-volume combustion bomb system for simulating self-combustion of gas at the tail end of a gasoline engine. The constant-volume combustion bomb system consists of a constant-volume combustion device, a fuel supply system, an ignition system, a high-speed photography system, a gas intake and exhaust system, a data acquisition system and a single-chip control system, wherein the constant-volume combustion device comprises a combustion bomb body with a cylindrical cavity; a main spark plug is mounted on the upper end surface of the combustion bomb body, at the end close to an oil injector, and an auxiliary spark plug is mounted close to the left end of the combustion bomb body; and the combustion bomb body is provided with a left window, a front window and a rear window and is further provided with the oil injector, a high-frequency response temperature sensor, a high-frequency response cylinder pressure sensor, a pressure transmitter mounting hole, a temperature transmitter mounting hole, an exhaust port and an intake channel. According to the invention, the main spark plug is adopted to simulate the normal flame ignition while the auxiliary spark plug is adopted to simulate self-combustion of gas at the tail end, so that self-combustion of gas at the tail end of the gasoline engine at all times can be simulated without the need of reaching high temperature and high pressure, and the constant-volume combustion bomb system is used for researching the influence of self-combustion of different tail-end gases to the cylinder internal pressure and detonation.

The invention relates to a detecting method for the failure of an automatic air brake system of a train, which comprises the following steps of: receiving and storing a train pipe pressure and a brake cylinder pressure transmitted by a sensor and acquired in a sampling period; obtaining first train pipe pressure and first brake cylinder pressure acquired in the sampling period as well as second train pipe pressure and second brake cylinder pressure acquired before a certain times of the sampling period; and judging whether the brake system is in failure according to the change of the first train pipe pressure relative to the second train pipe pressure and according to the change of the first brake cylinder pressure to the second brake cylinder pressure, wherein failure prompting information is output when the brake system is judged to be in failure. Correspondingly, the invention also relates to a detecting device for the failure of an automatic air brake system of a train, and monitoring and alarming equipment for the braking of the train. When the detecting method, the detecting device and the monitoring and alarming equipment are adopted, the online detection on the failure of the automatic air brake system of the train can be realized in real time, and the reliability and the accuracy of the detection result can reach a higher level.

Intake air is severely restricted during cold start of a diesel engine to provide high engine-out exhaust gas temperatures and quickly heat exhaust treatment devices. Cylinder pressures are maintained substantially below the pressure of the ambient atmosphere during a principal portion of the intake stroke of each combustion cycle to promote rapid fuel vaporization and higher combustion temperatures. The engine is operated in a premixed charge compression ignition combustion mode to provide a high engine-out exhaust temperature, stable combustion, and low emissions during the cold start period.