|LTCev diagram *
" EXTENDING RANGE THROUGH HIGHER FUEL EFFICIENCY "
US patent 8,683,987 B2
indirect pneumatic- coupling
Light Turbo Compound engine variant: LTCev 1
using a new unequal volume closed-loop efficient indirect pneumatic coupling induction system & method to achieve Otto cycle I.C.E. higher fuel efficiency
at sustained useful engine loads CAIC (throttled) Otto cycle S.I. engines and that is also beneficial and compatible with state of the art direct fuel injection system
S.I. & D.I. UAIC (Direct fuel injection) liquid fuel controlled engines
but also the LTCev is uniquely compatible with LPG / CNG gaseous fuels controlled system for S.I. gaseous fuel
unique "wet-sump /dry-sump" individually controlled cylinder-crankcase configuration VVICC providing ΔP indirect pneumatic-coupling turbo compound advantageously providing
affordable robust S.I.D.I. CAIC Otto cycle multiple cylinders engines not only the possibility to reduce pumping-loss friction but also to provide it with pumping-gain advantage ,
LTCev can also provide even higher pumping-gain advantage to state of the art C.I.D.I. UAIC Otto cycle engine to further enhance said engine's specific fuel efficiency
(without any increase of NOx emissions).
LTCev provides both pumping-loss neutralizing capability and pumping-gain advantage for S.I. Otto CAIC robust engine strategy that is
compatible with both liquid state fuel systems (gasoline/ethanol) including CNG) engines; as well as providing
pumping-gain being capable to further substantially improve the fuel efficiency of S.I. Otto UAIC ( GDI direct fuel injection system ) engines
and to effectively challenge the experimental DING natural gas engine project for cost effectiveness, flexibility, and reliability.
depending on the pre-determined specific Inverted Function Turbocharger's optimization:
pressure inside the cylinder.
1- The S.I. LTCev ( CNAIC) engine (using liquid fuel) is provided with the capability to cost effectively challenge gasoline Otto cycle S.I. UAIC
strategy engine GDI stratified direct fuel injection system's,
GDI's fuel-efficiency and prior art CAIC strategy S.I. gasoline and ethanol engines.
2- An OttoCycle S.I. LTCev ( CNAIC) using gazeous fuel throttled engine can be provided with a significantly part-load fuel efficiency
that can effectively and significantly extend the range of prior art S.I. Otto cycle S.I. CNG and LPG gaseous fuel system CAIC
strategy engines vehicles.
The S.I. LTCev provides higher part-load fuel efficiency, even with a simple, throttled ( CNAIC strategy ) engine, that uses a stable,
homogeneous charge intake cycle and does not have to rely on the critical and technically demanding UAIC strategy engine (direct fuel injection
system), that is a substantially more costly fuel system, characterized by not requiring nor using any intake air control means (or throttle) for
controlling engine power at part-load* ; direct fuel injection system is importantly advantageous because it does not generate detrimental intake-
cycle pumping-loss friction. Usual prior art Otto cycle CAIC strategy S.I. engine's fuel efficiency is normally, negatively affected by intake cycle
pumping-loss friction at engine part-load. Prior-art CAIC strategy engines ( throttled) suffer from increased specific fuel consumption at engine
part-load, ipso facto also increasing the emanation of GHG anthropogenic CO2 emissions.
* NOTE: part-load is the most prevalent and important engine operation range related to fuel efficiency affecting
personal transportation vehicle's operation, especially during long-distance cruising.
State of the art direct fuel injection system where is a fuel control system, where fuel only is controlled is a UAIC strategy is applicable for both
the Otto (S.I.) (gasoline) engine and the Otto (C.I) (Diesel) engine.
Indeed, UAIC strategy allows both the Otto cycle spark ignited (S.I.) and compression ignited (C.I.)engines to be totally immune from detrimental
pumping-loss friction at part-load.
The LTCev was originally devised as a robust, fail-safe, fuel efficient, CAIC lightweight engine strategy, providing a cost effective alternative to
direct fuel injection system and is compatible with multiple cylinders light aircraft usual and reliable, CAIC strategy S.I.engine, while safely
increasing the cruising range of said aircraft by reducing engine's part-load specific fuel consumption. By neutralizing part-load engine pumping-
loss- friction and providing advantageous pumping-assistance at higher engine load, it can achieve this task without needing to alter the robust
and stable CAIC strategy stoichiometric air-fuel air-fuel mixture by leaning-out the engine's air-fuel mixture and therefore always insure a
desirable fail-safe combustion process, neither having to rely on engine downsizing-compromise; as this compromise necessitates intensive
gearbox ratio reduction for providing suitable propeller rotational speed and torque .
Suitably optimized LTCev can compare with direct fuel injection fuel efficiency in regards to pumping-loss elimination, without the main
disadvantages of high development and production cost, mainly due to the fact that LTCev is simple, robust and does not suffer from direct fuel
injection's negative propensity to accumulate disruptive intake valves carbon build-up as a result of frequent and sustained light load engine
operation. Although new direct injection engine could operate without suffering from part-load pumping-loss, even whitout downsizing engine
displacement, downsizing compromise is still required for minimizing the direct injection system's negative propensity to accumulate disruptive
intake valves carbon build-up. Indeed, if said carbon build-up accumulation collects mainly to backside of intake valve and remains unattended,
it can seriously, negatively affects specific fuel consumption, reduce drive ability, ruin costly exhaust emission system and significantly increase
raw emissions levels.
Note: The recent emergence of interest in the automotive industry for the engine downsizing-compromise is due to the fact that it is technically
quite less costly (but much less effective) to proportionally reduce pumping-loss friction, by using a smaller displacement engine operating at
higher engine load and speed, requiring a wider throttle opening compromise, than opting for substantially more costly and technically advanced
state of the art UAIC direct fuel injection system; since pumping-loss is directly proportional to engine displacement volume and also directly
proportional to the severity of intake-cycle air-control CAIC (by throttling or other means).
The displacement related pumping-loss friction explains the demise of previously, cost-effective and trouble-free but "inadequately fuel-efficient
at engine part-load " CAIC ( throttled) prior art V-8 engines popular in earlier, larger, full size North American personal vehicles and medium
trucks operating mainly in an urban environment.
LTCev can provide higher fuel efficiency capability to robust low maintenance affordable S.I. Otto Cycle CAIC engine
The LTCev (CNAIC) effectively neutralizes said pumping-loss friction, without requiring any engine downsizing compromise (as direct fuel
injection system do). It is cost-effectively allowing, partial lowering of part-load specific fuel-consumption and proportionnally insures a
reduction of CO2 emission to the homogeneous-charge affordable S.I. Otto "Controlled-Air Intake-Cycle" CAIC strategy S.I. engine.
The LTCev neutralizes detrimental "engine displacement related pumping-loss friction to prevent usual CAIC fuel efficiency reduction at engine
part-load), and does it by conveniently and cost-effectively controlling both air and controlling fuel to achieve a stable and tolerant robust
combustion process without altering homogeneous air-fuel charge and combustion process's stability, Direct fuel injection system being a
significantly more sophisticated and more technically demanding system fuel-controlled-only and that must cope with uncontrolled air intake
cycle is also critically limited by time for providing adequately critical mixing and charging of the adequate homogeneous or stratified air/fuel-
mixture process to provide adequate combustion of air-fuel charge mixture in the cylinder.
An innovative approach allows neutralizing engine part-load pumping loss friction of CAIC S.I. engine. It can be uniquely achieved by means of
strategic timely closed-loop
pulsating pneumatic-coupling Δp = 0 turbo compound effects generated in unequal volumes individual cylinder crankcase.
Said Δp = 0 pressure condition being generated by an inverted function pulsating turbocharger* of the Light Turbo Compound engine variant. *
( Canadian patent CA 2,732,477 )
Although engine downsizing can be of proportional assistance, to reduce part-load pumping-loss friction, it could be more effectively achieved
only by using a substantially, more costly, more technically demanding and critical fuel system such as: Otto " Uncontrolled-Air Intake-Cycle "
ICUA strategy charge direct fuel injection system.
Otto cycle UAIC engine stategy compromises:
Because the LTCev can be optimized to be virtually immune (beyond idle) from displacement-related pumping-loss friction at engine useful part-load,
undesirable usual CAIC Otto cycle S.I. engine downsizing remains possible but is NOT mandatory and compromises 1 - 6 are no longer issues
undesirable UAIC (direct fuel injection system)'s risk of intake valve carbon accumulation (compromise 7) is not an issue for the LTCev.
and neither are the following:
Otto cycle LTCev CNAIC engine strategy advantage: By retaining the advantageous characteristics of the affordable and widely popular S.I. Otto cycle
Controlled-Air Intake-Cycle CAIC engine"that provides stable and robust combustion characteristics due to stoichiometric air-fuel homogeneous intake-
cycle charge mixture; CAIC strategy's simplicity, reliability and flexibility can now be advantageously complemented with a significant part-load
improvement of fuel-efficiency which furthermore only requires less critical, proven, efficient and affordable fuel control system.
Since the most prevalent and useful engine operating range of any Otto cycle engine for personal transportation occurs at engine part-load, the LTCev is ideally suitable for
reducing dependency of fossil fuel for extended range personal vehicles and as well as electric hybrid and mild hybrid vehicles
pumping-assistance capability to further improve specific fuel efficiency without inevitably increasing NOx emission.
Spark Ignited (S.I.) Otto Cycle throttled internal combustion engines
suffer from parasitic pumping losses associated with partial vacuums developed in
their intake manifolds and in the cylinders above their pistons,
as is illustrated in fig. pv8AA.dwg .
This drawback is most prevalent when a S.I. Otto cycle engine is operated at
part-load with the throttle partially closed. During each intake cycle of of a throttled
Otto S.I. engine CAIC (controlled air intake cycle); operating at part-load, extra
pumping work must be done by the piston as it draws the air-fuel
mixture from the intake manifold into the volume expanding cylinder to counteract a
force on the opposing face of the piston due to a pressure imbalance intake delta P
existing in the cylinder volume above the piston and in particular the crankcase
volume below the piston. This extra work negatively affects the engine’s specific fuel
consumption and its level of anthropogenic emission and is the major drawback for
vehicles requiring the use of larger displacement throttled engines in extended range
operations and in engine applications requiring a wide flat responsive power curve.
Eliminating part-load pumping-loss friction is an important Otto cycle fuel
efficiency advantage that could previously mainly only be provided
by direct fuel injection system.( fig.pv8AB.dwg)
|hic inceptant futura
|R&D MACHMA INC
| as direct fuel injection system
LTCev controls pumping-loss of current low pressure natural gas NGV fuel control systems
|R&D MACHMA INC
|Turbo compound systems to recover energy in ICE