LTCev diagram *


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:
  • LTCev  can  be optimized to cost effectively provide ΔP=0  beneficial neutralizing effect to pumping-loss friction of "throttled" engine

    (CAIC) controlled-air intake-cycle) as Gasoline Direct Fuel Injection system  to reduce part-load SPECIFIC FUEL CONSUMPTION

  • LTCev can be optimized to provide (CAIC) controlled-air intake-cycle)  intake cycle pumping-gain ΔP<0 assistance at higher engine load beneficial to all Otto cycle C.I. & S.I.

  • LTCev can advatageously use the ambient barometric air pressure energy exerted onto a piston crown during Otto intake cycle  
in conjunction with the alternate underpressure created in a VVICC ( individual cylinder crankcase) to allow turbo compound indirect pneumatic coupling provided by available ambient atmospheric
pressure inside the cylinder.
  • LTCev is capable (due  to ΔP<0 air pressure ) to be optimized to provide intake-cycle pumping-gain assistance further ENHANCING fuel efficiency of state of the art                            
    turbocharged * UAIC (uncontrolled-air intake-cycle) "direct fuel injection system" S.I. & C.I. engines and  more than the limited pumping-gain provided by the *(S.I. Ford Ecoboost,                               
    &  C.I. VW TDI)  that are possible only for a more modest intake cycle pumping-gain ΔP<0 assistance at higher engine load because any direct pneumatic coupling pumping-gain                                   
    inevitably raises dynamic compression ratio, resulting in more  raw  NOx emission.

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.
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:

  • 1- higher fabrication cost due to downsized engine, higher MEP, higher RPM  and operating strain,
  • 2- mandatory downsized engine reduced operational engine flexibility3- inevitable higher NOx emission level,
  • 4- higher engine operating speed and narrower power band requiring multiples gear and gear changes,
  • 5- user perception, of affected engine longevity,
  • 6- narrower power band with lower low-end torque requiring extensive number of gear ratios.
  • 7- vulnerability of intake valve carbon accumulation build-up following cumulative frequent  and sustained low engine load operation, and not stricly
    adhered frequent and regular oil change schedule.     US 6866031 B2   VW

  • It is important to note that those compromises can now become unnecessary and can now be avoided without negatively affecting engine part-load
    fuel efficiency and allowing to freely opt for the ideal required engine displacement size due to the new opportunity to use the light turbo compound
    engine variant strategy for affordable personal extended range transportation vehicle.

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

  • 1  MINIMAL NEGATIVE HOLISTIC ENVIRONMENTAL IMPACT:  minimal contributing GHG CO2 emissions, HC & NOx emissions

  • 2  HIGH FUEL EFFICIENCY:  focus on extended range personal vehicle utilisation (using fossil, renewable bio-fuel and gaseous fuel )

  • 3  COMPATIBILITY: with existing and proven state of the art Otto cycle technologies & alternate fuels insures cost-effectiveness
  • retrofit and reliability

  • 4  Pumping-Gain Assistance-Capability: conveniently provided by available ambient atmospheric* pressure assistance (P2)
    to provide a ΔP condition where  Δp< 0 such that at higher engine CAIC operating loads Δp < 0 results in beneficial
    pumping-assistance capability to further improve specific fuel efficiency without inevitably increasing NOx emission.
  • 5 LTCev CAIC engines can be more robust (less vulnerable to deposit of carbon on intake valve) than GDI system (UAIC strategy)

The LTCev can prove useful to rationalize
cost for manufacturing flexible and fuel
efficient  Otto cycle I.C.E. components for
electric hybrids  and for extended range
vehicle's engine; simultaneously capable
of lowering raw NOx and HC emissions, as
well as lowering CO2 emissions.
LTCev's "supplemental " pumping-gain assistance capability for
UAIC  could be used to further improve  turbocharged/ direct fuel injected intake
cycle pumping-gain advantage of UAIC engine such as:
Ford's EcoBoost S.I. engine or VW TDI C.I.engine,
but can further improve fuel efficiency while not increasing their NOx emission.
CA 2,732,477

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

Light Turbo Compound unique closed-loop-ΔP pneumatic coupling can uniquely  match UAIC strategy
(direct fuel injection) engine intake cycle efficiency at part-load by eliminating Otto intake cycle pumping-
loss friction of throttled
lagom* engine (CAIC strategy), adequately using an
inverted- function-turbo charger providing more
Intake cycle Pumping-gain at higher engine loads and
can cost effectively challenge turbo-charged and
direct fuel injection system engine such as
John B. Haywood's group's (Ford's S.I. Ecoboost engine) that uses both a usual
function turbocharger and GDI
at higher engine loads
BMEP, but unlike the Ford ecoboost , it can do so without simultaneously,
normally increasing said engines's raw NOx emission.
LTCev can neutralize pumping-loss Otto cycle CAIC (throttled) engine nearly fully achieving  GDI Gasoline
Direct fuel Injection system's no-pumping-loss ability,
but can provide higher fuel efficiency (without any NOx increase) through providing  intake-cycle
assistance to
S.I. Otto cycle UAIC
(Gasoline Direct Fuel Injection system) engine and to C.I. Otto cycle UAIC (
common-rail diesel )
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R&DMI 03-21-2014
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R&DMI 03-21-2014
                                           as direct fuel injection system
LTCev controls pumping-loss of current
 low pressure natural gas NGV fuel control systems  
Turbo compound systems to recover energy in ICE
LTCev 2.3A.dwg
gaseous state
fuel systems