Electromagnetic Shut-off Valve for Otto Engine Pumping Loss
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Solution Overview
Problem
Pumping loss in Otto-cycle internal combustion engines is unavoidable due to the energy loss from drawing air through a restricted throttle, which is not present in diesel engines with direct fuel injection, and previous methods to reduce this loss have disadvantages such as complex valve gears or increased emissions.
Innovation Solution
An Otto-cycle internal combustion engine with an electromagnetically operated shut-off valve upstream of the inlet valve, which synchronizes with the engine cycle to open and close the suction passage, reducing airflow resistance and allowing for efficient shut-off of fluid flow during the induction stroke, thereby minimizing energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a throttle is used to control power output in an Otto-cycle engine, then power output can be reduced, but pumping loss increases due to energy loss from drawing air through a restricted orifice
Solution Approach 1:
The patent divides the inlet flow control into two separate valves: a throttle valve for power control and a shut-off valve for eliminating pumping loss. This segmentation allows each valve to perform its specific function optimally - the throttle valve controls power output while the shut-off valve eliminates the harmful suction effect during the intake stroke
Solution Approach 2:
The shut-off valve acts as an intermediary component that eliminates the harmful pumping effect by closing the suction passage during the intake stroke, while the throttle valve remains open to allow free airflow. This intermediary valve mediates between the need for power control and the need to eliminate energy loss
2Loss of energy
If a control valve is added upstream of the inlet valve to reduce pumping loss, then energy loss decreases, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical valve gear systems with an electromagnetically operated shut-off valve. This electromagnetic actuation system is simpler and more reliable than traditional mechanical linkage systems, reducing device complexity while achieving the goal of eliminating pumping loss
Solution Approach 2:
The control unit integrates multiple functions including throttle valve control, shut-off valve control, and coordination of both valves to work together. This universal control system manages the entire valve operation from a single controller, simplifying the overall system architecture despite adding a new valve
3Loss of energy
If the shut-off valve closes the suction passage during the induction stroke, then pumping loss is reduced, but airflow restriction increases
Solution Approach 1:
The shut-off valve operates periodically, closing during the induction stroke to eliminate pumping loss and opening during other strokes to allow free airflow. This periodic action ensures that airflow restriction only occurs when necessary to eliminate energy loss, while maintaining free flow during combustion and exhaust strokes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces pumping loss by allowing the shut-off valve to control airflow and fuel injection dynamically, enhancing engine efficiency and power delivery while minimizing emissions and complexity.
Implementation Method 1
the valve is provided with a magnetic field generator which generates a radial magnetic field relative to the axis of the valve to cause axial movement of the ring
Implementation Method 2
the ring is provided with an electrically conductive filament and the valve is provided with a magnetic field generator which generates a radial magnetic field
Data Source
Figure 1
Figure 1a
Figure 2a
AI summary
An Otto cycle internal combustion engine (10) provided with a combustion chamber (14) and an inlet (18) and an outlet (20) with respective valves (24 and 26), and a suction passage (29) leading to the said at least one inlet (18) to conduct the flow of fluid material thereto. The engine (10) further comprises a control valve (28) arranged upstream of the inlet valve (24) and being operable to change between a condition in which it opens the suction passage (29) and a condition in which it closes the suction passage (29). An engine operating position sensor (90) provides signals indicative of the operating position of the engine (10). There is also an engine power control (92). A variable intermediate position control signal generator (95), generates control signals at times respectively between the beginning and the end of each of a succession of inlet valve opening periods of the engine cycle. It is connected to receive signals from the engine operating position sensor (90) and the engine power control (92) and to send the control signals to the control valve (28) in such a manner that in between an opening of the inlet valve (24) and the immediately following closure thereof there is a period in which the suction passage (29) is open and a period in which it is closed, the period for which it is open being in dependence upon the engine power control (92) output. The invention extends to a method of operating such an engine (10).