Technologies

Engines & Power Electronics : Automotive

Technologies

New Rotor Magnet Configuration Delivers Greater Efficiency at a Lower Price

UW–Madison researchers have developed a streamlined sinusoidal rotor magnet design for interior permanent magnet machines.

By altering the classic rectangular block design for embedded magnet stacks in favor of a sinusoidal, axially varied orientation, researchers have increased the efficiency of rotors in IPMMs in a twofold fashion: Not only does this new design reduce the amount of magnet material necessary for rotor production, but it also provides an optimized distribution of flux that significantly reduces torque pulsation and spatial harmonics. The new design is easy to manufacture and is complementary to rotors already in existence.
P150363US01

Axial Flux-Switching Permanent Magnet Machine for High Speed Operation

UW–Madison researchers have developed a new axial FSPM machine that can be run at high speed with less fundamental frequency required, therefore overcoming one of the largest barriers to adoption. The new design features innovative axial flux topologies with offset rotor and/or stator structures.
P150249US01

Flux-Switching Permanent Magnet Machine for High Speed Operation

UW–Madison researchers have developed a new FSPM machine that can be run at high speed with less fundamental frequency required, therefore overcoming one of the largest barriers to adoption. The new design relies on innovative radial flux topology that features an offset rotor structure, dual stators and concentrated coil windings.
P140405US01

Fuel Reactivity Method Cuts Diesel Engine Emissions

UW–Madison researchers have developed a smarter combustion process using in-cylinder fuel blending. The process is called Reactivity Controlled Compression Ignition (RCCI) combustion.

RCCI utilizes at least two fuels of different reactivity and multiple injections to control the timing and duration of combustion. In the process, a low reactivity fuel (e.g., gasoline) is introduced into the cylinder and mixed with air. Then, high reactivity fuel (e.g., diesel) is injected using single or multiple injections. This helps tailor the combustion process for optimal power output at a controlled temperature (to address NOx) and with controlled equivalence ratios (to address soot).
P100054US02

Improved Compression Ignition Combustion in Rotary Engines for Higher Efficiency and Lower Pollutant Emissions

The UW–Madison researchers now have adapted their previous RCCI method for use in rotary engines. The system comprises a rotor with a circumference having two or more rotor faces where a chamber is defined between each rotor face and the housing. A similar fuel mixture method is used in which a first fuel charge is provided to one of the chambers and then a second fuel charge with different reactivity is provided to a different location in the chamber containing the first fuel charge so as to set up an optimal reactivity stratification. The chamber receiving the first and second fuel charges lacks a spark plug or other spark source; thus, the fuel charge having higher reactivity initiates combustion within the chamber.
P110320US01

Engine Combustion Control at Low Loads with Reactivity Controlled Compression Ignition Combustion

UW–Madison researchers now have developed a compression combustion method for an internal combustion engine to enable low emissions and high thermal efficiency at low engine loads. The combustion engine has tanks containing fuel materials with differing reactivities. Fuel from the tanks is provided to the combustion chamber during an engine combustion cycle when the engine is running to obtain a stratified distribution of fuel reactivity within the combustion chamber, with regions of high reactivity spaced from regions of low reactivity. The fuels are provided to the combustion chamber at different times during the engine combustion cycle.

The internal combustion engine also has a throttle upstream from its intake port, which allows an open state allowing maximum airflow from the intake manifold to the intake port and a closed state allowing minimum airflow from the intake manifold to the intake port. The throttle is kept out of the open state during the intake stroke of the combustion cycle so that the cylinder air pressure is below ambient pressure at the start of the compression stroke, resulting in controlled temperatures, equivalence ratios, soot and emissions and increased fuel efficiency.
P110092US01

RCCI – A Clean Compression Engine Combustion Process for High Fuel Efficiency and Low Emissions

UW–Madison researchers have developed a compression engine combustion process using in-cylinder fuel blending. The system utilizes at least two fuels of different reactivity and multiple injections to control in-cylinder fuel reactivity to optimize combustion phasing, duration and magnitude. The process involves introduction of a low reactivity fuel into the cylinder to create a well-mixed charge of low reactivity fuel, air and recirculated exhaust gases. The high reactivity fuel is injected using single or multiple injections directly into the combustion chamber.

In this combustion process, the combusting phasing and duration are controlled by the auto-ignition characteristics, or reactivity of the charge; thus, the combustion mode was named Reactivity Controlled Compression Ignition (RCCI) combustion. Figure 1 shows a typical setup for RCCI combustion using port-fuel-injection of a low reactivity fuel (e.g., gasoline) and direct-injection of a high reactivity fuel (e.g., diesel fuel).

By appropriately choosing the reactivities of the fuel charges, their relative amounts, timing and combustion can be tailored to achieve maximum fuel efficiency. This methodology has resulted in what is believed to be the most fuel-efficient internal combustion engine currently known that is also capable of meeting government soot and NOx emissions limits (see related publication below). Figure 2 shows a summary of results at identical operating conditions for an engine operating in the RCCI combustion mode and state-of-the-art conventional diesel combustion mode. In addition to the improved efficiency, (i.e., reduced greenhouse gas emissions) due to reduced heat transfer losses and improved control over the combustion event, RCCI combustion has demonstrated a factor of 100 reduction in NOx emissions and a factor of 10 reduction in soot emissions.
P100054US01

Adaptive Fuel Injection Method Cuts Diesel Engine Emissions

UW–Madison researchers have developed a new adaptive injection technique to reduce NOx and soot emissions from diesel engines.

For low engine loads, one or more fuel injections take place between the intake and compression strokes. Each injection has increasing pressure, making the fuel highly premixed with air in the combustion chamber.

For greater engine loads, the process has two steps. First, injections of increasing pressure take place between the intake and compression strokes. Then, subsequent injections occur between the compression and expansion strokes. These subsequent injections have variable pressure. Such variation in injection pressure helps the fuel penetrate within the combustion chamber. At the same time, the pressure is modified so that fuel does not impinge on the walls of the chamber, which would worsen fuel economy and emissions. The technology can readily be implemented using an engine equipped with two fuel injectors per cylinder (each operated with different injection pressures), or with a single injector featuring variable injection pressure, as described in WARF reference number P01108US.
P07342US

Valve Method Cuts Engine Emissions, Boosts Combustion

UW–Madison researchers have developed a way to exploit the flexibility of VVA and reduce pollutant emissions from internal combustion engines.

Their method employs VVA to open valves not only during the intake and exhaust strokes (as in conventional engines), but also at optimal times during the compression and/or power stokes. Briefly opening the valves at these times promotes turbulence and more fuel-air mixing in the combustion chamber, resulting in much greater soot oxidation.

Any unburned fuel or particulates that escape through open valves via the intake manifold will be ingested during the next engine cycle and thus won’t contribute to emissions. Also, to reduce the loss of combustion chamber pressure (and thus engine power) while the valves are open, the length of time they are open can be minimized easily with VVA.
P06042US

Variable Valve Actuation Method to Enhance Combustion and Reduce Engine Emissions

UW-Madison researchers have now devised a way to exploit the flexibility of VVA to reduce pollutant emissions from internal combustion engines. Their method employs VVA to open valves not only during the intake and exhaust strokes as in conventional engines, but also at optimal times during the compression and/or power stokes. Opening the valves at these times promotes in-chamber turbulence and mixing during combustion, resulting in much greater soot oxidation. Any unburned fuel or particulates that escape through open valves via the intake manifold will be ingested during the next engine cycle and thus won’t contribute to emissions. Also, to reduce loss of combustion chamber pressure (and thus, engine power) during valve opening, the length of time the valves are open can be minimized easily with VVA.
P03152US

Reducing Emissions and Controlling Combustion Phasing in HCCI Engines

UW-Madison researchers have now developed a method to effectively control combustion phasing in direct-injection, compression-ignition engines by using suitably timed multiple fuel injections. In this technique, an initial fuel pulse is injected during the early phase of the compression stroke. The pulse is timed to mix with cylinder air so that it is too “lean” to produce appreciable soot and nitrogen oxides upon combustion, but not so lean that it creates significant amounts of unburned hydrocarbons and carbon monoxide.

Normally, the pulse is also too lean to auto-ignite, leading to problems with combustion phasing. To solve this, the researchers inject a second fuel pulse that provides a locally rich fuel mixture for effective auto-ignition. They have optimized the second injection’s timing and amount to reduce the soot and nitrogen oxides normally resulting from a single, late fuel injection.
P01320US

Use of Multiple Injections of Increasing Pressure to Reduce Diesel Engine Emissions

UW-Madison researchers have developed a multiple fuel injection scheme that should simultaneously reduce both nitrogen oxide and particulate emissions from diesel engines. Instead of injecting a single fuel charge during a combustion cycle, several charges are injected. Each charge carries an amount of fuel that when added together equals the single charge and is injected at a higher pressure than the last. Spacing fuel injections into several charges of increasing pressure enlarges the surface area of the soot clouds that are exposed to oxidation. It also maintains more uniform combustion temperatures, leading to cooler engine conditions and lower nitrogen oxide emissions. This technique provides higher combustion chamber mixing and greater soot oxidation rates even during the power stroke when mixing rates are reduced due to piston expansion.
P01108US

Variable Valve Timing Actuator

UW–Madison researchers have developed a valve actuator that allows engine valves to be variably and individually controlled without the use of a camshaft. The actuator utilizes energy regeneration so that energy delivered to a valve while it is accelerating is recovered while it is decelerating. The variable valve timing actuator comprises a valve, a spring charger assembly, at least one spring and at least one latch.

The valves are held stationary by a latch which is disengaged when the valve is to begin opening or closing. The latch allows the valve to automatically lock in its open or closed position without the need for a control input; also, no energy is required to hold the valves in a given position. The springs impose an opening force on the valve and once the valve is open, the opposing springs impose a closing force on the valve. Thus, the motion of the valve through a complete cycle may be affected by simply altering the state of the latches, which allows the springs to drive the valve towards an open or closed position.
P97166US

Magneto Rheological Fluid High Torque Transfer Device for Improved Clutch Design

UW-Madison researchers have developed an improved MR clutch design. This MR clutch achieves high torque transfer without increasing power consumption and maintains the footprint of the device.

The clutch is composed of a drum-shaped rotor, which has a rotational degree of freedom with respect to a cylindrical stator and magnetic field generator. The stator and rotor define an annular, or ring shaped, space between the two that can be filled with the MR fluid. The magnetic field generator produces a radially directed magnetic field across the annular space that causes stationary stripes of magnetizable particles in the MR fluid to form and create a fluid couple between the rotor and stator. The stator and rotor are configured with ring-like flow channels that aid in the creation of the magnetized particle strips, thus increasing the transferred torque.
P05444US