<div class="section abstract"><div class="htmlview paragraph">The property of methanol to surface ignite can be exploited to use it in a diesel engine even though its cetane number is very low. Poor lubricity of methanol is still an issue and special additives are needed in order to safeguard the injection system components. In this work a common rail three cylinder, turbocharged diesel engine was run in the glow plug based hot surface ignition mode under different injection strategies with methanol as the main fuel in a blend with n-butanol. n-Butanol was used mainly to enhance the viscosity and lubricity of the blend. The focus was on the effect of different injection strategies. Initially three blends with methanol to n-butanol mass ratios of 60:40, 70:30 and 80:20 were evaluated experimentally with single pulse fuel injection. Subsequently the selected blend of 70:30 was injected as two pulses (with almost equal mass shares) with the gap between them and their timing being varied. Finally the effect of mass share of the injection pulses was evaluated. All the experiments were done at a speed of 1800 rpm, Brake Mean Effective Pressure (BMEP) of 8 bar and injection pressure of 850 bar and performance, emissions and combustion parameters were analyzed.</div><div class="htmlview paragraph">Higher methanol shares increased the efficiency because of controlled combustion rates and proper combustion phasing. Enhancing the methanol share, due to its high latent heat of vaporization lowered the temperatures and the Oxides of Nitrogen (NO<sub>x</sub>) levels with near zero smoke levels. However, Hydrocarbon emission (predominantly formaldehyde and methanol) was found to be higher but it was possible to reduce it by using a diesel oxidation catalyst. Double pulse injection resulted in an improvement in the brake thermal efficiency due to better combustion phasing. Reduced the rate of pressure rise and NO<sub>x</sub> emissions were also observed. An almost equal share between the two injection pulses was found to be acceptable and the efficiency was better than the base diesel engine with negligible smoke and lower NO<sub>x</sub> levels.</div></div>
<div>In Asian countries, small two-wheelers form a major share of the automobile
segment and contribute significantly to carbon dioxide (CO<sub>2</sub>)
emissions. Hybrid drives, though not widely applied in two-wheelers, can reduce
fuel consumption and CO<sub>2</sub> emissions. In this work three hybrid
topologies, viz., P2 (electric motor placed between engine and transmission), P3
(electric motor placed between transmission and final drive), and power-split
concepts (with planetary gear-train) have been modeled in Simulink, and their
fuel consumption and emissions under the World Motorcycle Test Cycle (WMTC) have
been evaluated. A physics-based model for the Continuously Variable Transmission
(CVT) was used which is capable of predicting its transient characteristics. A
map-based fuel consumption model and a Neural Network (NN)-based transient
emission model were used for the engine. The NN-based transient emission model
avoids the need to model the air path and fuel path in transient conditions,
which is time consuming. The fueling characteristics of the Engine Control Unit
(ECU) in transients need not be known if an NN model is built and tuned with
sufficient experimental data. Several transient experiments were performed with
speed-load profiles similar to the WMTC for tuning the NN emission models.
Simulation results show that the P2 hybrid, P3 hybrid, and power-split drives
have fuel economy benefits of about 27%, 37%, and 49%, respectively, compared to
the conventional powertrain. However, nitrogen oxides (NOx) emissions are much
higher for the hybrid powertrains due to the operation of the engine at higher
load ranges for efficiency but are still within the prevailing BS6 Indian
emission limits. A significant portion of the wheel energy input can be
recovered through efficient regenerative braking in the WMTC. This will be even
more significant under peak traffic city driving conditions. The belt losses in
the CVT significantly reduce the potential benefits of the hybrid powertrain,
and hence, an efficient transmission to replace it will be beneficial.</div>
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