DigitalAir™ Camless FVVA System – Part 1, Valve Train Design, Capability and Performance

Babbitt, Guy; Rogers, Jeff; Weyer, Kristina M.; Cohen, Drew; Charlton, S J

doi:10.4271/2017-01-0635

Cited by 2 publications

(7 citation statements)

References 13 publications

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“…With vertical slots in the intake valve, the swirl ratio is effectively zero. However, as discussed in Part 1 of this paper [1], the swirl in the cylinder may be tuned by tilting the slots to the vertical, for example by 20 degrees.…”

Section: Motored Engine Cfd Resultsmentioning

confidence: 99%

“…This design has limitations in full lift accuracy and power consumption. The latest design described in the companion paper [1] and shown in Figure 17, uses a center-biased actuator giving tighter control and energy recovery for low power consumption. The test setup uses a Parker electric motoring / absorbing dynamometer, closed-loop control of oil, fuel and coolant temperatures, and National Instruments data acquisition.…”

Section: Methodsmentioning

confidence: 99%

“…This first generation spring-biased solenoid actuation leads to bounce and excessive variation when fully open. This should improve significantly with the next generation center-biased solenoid actuator under development [1]. However, it appears that the accurate and consistent event timing is the more important characteristic at this operating condition.…”

Section: Intake Valve Load Controlmentioning

confidence: 97%

“…The DigitalAir Concept Figure 1 shows a cross-section of the DigitalAir system developed by JP SCOPE Inc. DigitalAir replaces the poppet valve with horizontally acting slotted valves, which provide the full flow area with a very short stroke compared with a poppet valve [21][22][23][24][25]. This approach provides advantages over electro-hydraulic camless poppet valve systems, such as: As with any new technology, this approach does raise some obvious questions, which are being addressed and will be discussed further in this paper and in the companion paper [1], for example:  Volume of slots added to the combustion chamber  Sealing between cylinder and ports  Surface area, heat transfer and cooling of the valve bridges  Potential for quenching and hydrocarbons in the slots …”

Section: Bmw Valvetronic [9]mentioning

confidence: 99%

“…Power consumption is discussed in detail in the companion paper [1]. The actuator has been designed to minimize power consumption by adopting a center-biased approach, wherein the neutral position of the valve is the mid positon between fully open and fully closed, see Figure 17.…”

Section: Power Consumptionmentioning

confidence: 99%

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DigitalAir^™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities

Charlton¹,

Price²,

Rogers³

et al. 2017

SAE Int. J. Engines

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The paper describes a completely new approach to fully variable valve actuation (FVVA), which allows almost unlimited continuously variable control of intake and exhaust valve opening and closing events, and duration without the use of a camshaft. DigitalAir replaces conventional poppet valves with horizontally actuated valves located directly above the combustion deck of the cylinder head, which open and close a number of slots connecting the cylinder with the intake and exhaust ports, Figure 1. The stroke of the valves to provide the full flow area is approximately 25% of the stroke of the equivalent poppet valve, thus allowing direct electrical actuation with very low power consumption. This design arrangement also avoids the risk of poppet valve to piston collision, or the need for cutouts in the piston crown, since the valves do not open into the cylinder. The paper will present analytical and experimental data which confirms that the proposed FVVA system can meet the basic performance requirements of modern GDI engines with respect to breathing characteristics across the speed range, throttleless operation at and above idle, opening and closing event optimization, cylinder deactivation, control of residual gas fraction / scavenging and exhaust thermal management. Analytical results were developed using GT-POWER Cycle Simulation and CONVERGE computational fluid dynamics (CFD). Cycle simulation was used to study the system level performance, such as full load capability and transient response, and in particular to quantify the fuel consumption benefits of throttleless operation. CFD was used to better understand the opportunities for in-cylinder charge motiontumble, swirl and turbulence. JP SCOPE Inc. has been running experimental engines with DigitalAir for several years and has successfully completed performance and durability tests. The mechanical and thermal design of the cylinder head, and the design of the actuator will be covered in Part 1 of this paper [1].

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Section: Motored Engine Cfd Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Intake Valve Load Controlmentioning

confidence: 97%

Section: Bmw Valvetronic [9]mentioning

confidence: 99%

Section: Power Consumptionmentioning

confidence: 99%

See 3 more Smart Citations

DigitalAir^™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities

Charlton¹,

Price²,

Rogers³

et al. 2017

SAE Int. J. Engines

Self Cite

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show abstract

Measurement and modelling of a linear electromagnetic actuator driven camless valve train for spark ignition IC engines under full load condition

Yang

Liang

2021

Mechatronics

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DigitalAir™ Camless FVVA System – Part 1, Valve Train Design, Capability and Performance

Cited by 2 publications

References 13 publications

DigitalAir^™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities

DigitalAir^™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities

Measurement and modelling of a linear electromagnetic actuator driven camless valve train for spark ignition IC engines under full load condition

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DigitalAir™ Camless FVVA System – Part 1, Valve Train Design, Capability and Performance

Cited by 2 publications

References 13 publications

DigitalAir™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities

DigitalAir™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities

Measurement and modelling of a linear electromagnetic actuator driven camless valve train for spark ignition IC engines under full load condition

Contact Info

Product

Resources

About

DigitalAir^™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities

DigitalAir^™ Camless FVVA System - Part 2, Gasoline Engine Performance Opportunities