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US 4,539,948 AGranted
Two-cycle diesel engine and method for methanol and like fuel operation
AssigneeGeneral Motors Corporation
InventorRichard R. Toepel
Life of this patent
Estimating the term…
Abstract
A two-stroke cycle blower charged diesel engine is adapted for compression ignition operation on methanol or other low cetane fuels by modifications primarily including means for limiting cylinder charging air to a low scavenge ratio that provides heating of the cylinder charge with exhaust residuals to a point where reliable compression ignition of injected methanol, or other, fuel occurs. Preferably, a reduced flow air supply system and a controlled blower bypass provide adequate cylinder charge temperatures for methanol autoignition. Glow plugs or other means may be included for starting and warm-up operation.
Claims6
A two-stroke cycle diesel engine adapted for compression ignition operation on liquid fuels, said engine comprising
- a plurality of cylinders having pistons operable on a two-stroke cycle including compression and power strokes to supply power to an output member and permit through-flow cylinder scavenging at the end of each power stroke,
- an air supply blower connected to the cylinders to supply scavenging air thereto
- injection means to inject liquid fuel into each cylinder near the end of its piston compression stroke for compression ignition and burning of the fuel in a compressed charge, the compression ratio of the engine being inadequate in at least some portion of the normal operating range to raise a full cylinder charge of ambient air to a temperature capable of reliably igniting the injected fuel without substantial preheating or precompression of the cylinder charge, and
- means limiting the flow of scavenging air to the cylinders in at least a portion of the engine operating range to provide a cylinder scavenging ratio of sufficiently less than 1.0 to produce a heating effect of residual exhaust gases remaining in the cylinder that will raise the charge temperature to a point where reliable self-ignition of the fuel will occur substantially upon its injection into the compressed cylinder charge.
1 more element
A two-stroke cycle diesel engine adapted for compression ignition operation on low cetane liquid fuels, said engine comprising
- a plurality of cylinders having pistons operable on a two-stroke cycle including compression and power strokes to supply power to an output member and permit through-flow cylinder scavenging at the end of each power stroke,
- an air supply blower connected to the cylinders to supply scavenging air thereto
- injection means to inject liquid fuel into each cylinder near the end of its piston compression stroke for compression ignition and burning of the fuel in a compressed charge, the compression ratio of the engine being inadequate under some conditions to raise a full cylinder charge of ambient air to a temperature capable of reliably igniting the injected fuel without substantial preheating or precompression of the cylinder charge, and
- non-restrictive means limiting the flow of scavenging air from the blower in at least a portion of the engine operating range to provide a cylinder scavenging ratio of sufficiently less than 1.0 that the heating effect of residual exhaust gases remaining in the cylinder will raise the charge temperature to a point where reliable self-ignition of the fuel will occur substantially upon its injection into the compressed cylinder charge.
1 more element
A two-stroke cycle diesel engine adapted for compression ignition operation on liquid fuels, said engine comprising
- a plurality of cylinders having pistons operable on a two-stroke cycle including compression and power strokes to supply power to a crank and permit through-flow cylinder scavenging at the end of each power stroke,
- an air supply blower connected to the cylinders to supply scavenging air thereto
- injection means to inject liquid fuel into each cylinder near the end of its piston compression stroke for compression ignition and burning of the fuel in a compressed charge, the compression ratio of the engine being inadequate to raise a full cylinder charge of ambient air to a temperature capable of reliably igniting the injected fuel without substantial preheating or precompression of the cylinder charge, and
- means for varying the effective output of scavenging air from the blower in at least a portion of the engine operating range to provide a cylinder scavenging ratio sufficiently low that the heating effect of residual exhaust gases remaining in the cylinder will raise the charge temperature to a point where reliable self-ignition of the fuel will occur substantially upon its injection into the compressed cylinder charge.
1 more element
A two-stroke cycle diesel engine adapted for compression ignition operation on low cetane liquid fuels, said engine comprising
- a plurality of cylinders having pistons operable on a two-stroke cycle including compression and power strokes to supply power to a crank and permit through-flow cylinder scavenging at the end of each power stroke,
- an air supply blower connected to the cylinders to supply scavenging air thereto
- injection means to inject liquid fuel into each cylinder near the end of its piston compression stroke for compression ignition and burning of the fuel in a compressed charge, the compression ratio of the engine being inadequate to raise a full cylinder charge of ambient air to a temperature capable of reliably igniting the injected fuel without substantial preheating or precompression of the cylinder charge, and
- blower bypass means operative to vary the effective output of scavenging air from the blower in at least a portion of the engine operating range to provide a cylinder scavenging ratio sufficiently low that the heating effect of residual exhaust gases remaining in the cylinder will raise the charge temperature to a point where reliable self-ignition of the fuel will occur substantially upon its injection into the compressed cylinder charge.
1 more element
A two-stroke cycle diesel engine adapted for compression ignition operation on low cetane liquid fuels and/or at low compression ratios, said engine comprising
- a plurality of cylinders having pistons operable on a two-stroke cycle including compression and power strokes to supply power to a crank and permit through-flow cylinder scavenging at the end of each power stroke,
- an air supply blower having a positive displacement impeller and connected to the cylinder to supply scavenging air thereto
- injection means to inject liquid fuel into each cylinder near the end of its piston compression stroke for compression ignition and burning of the fuel in a compressed charge, the compression ratio of the engine being inadequate to raise a full cylinder charge of ambient air to a temperature capable of reliably igniting the injected fuel without substantial preheating or precompression of the cylinder charge,
- modulated blower bypass means operable to vary the flow of scavenging air from the blower and
- control means to modulate the bypass means to obtain a sufficient heating effect of residual exhaust gases remaining in the cylinder to provide cylinder charge temperatures adequate for reliable self-ignition of the fuel substantially upon its injection into the compressed cylinder charge.
2 more elements
A two-stroke cycle diesel engine adapted for compression ignition operation on low cetane liquid fuels, said engine comprising
- a plurality of cylinders having pistons operable on a two-stroke cycle including compression and power strokes to supply power to a crank and permit through-flow cylinder scavenging at the end of each power stroke,
- a turbocharger feeding an air supply blower having a positive displacement impeller and connected to the cylinders to supply scavenging air thereto
- injection means to inject liquid fuel into each cylinder near the end of its piston compression stroke for compression ignition and burning of the fuel in a compressed charge,
- glow plugs in the cylinders to aid ignition during starting and low temperature operation,
- modulating blower bypass means operable to vary the flow of scavenging air from the blower, and
- bypass control means operative to control the blower bypass means to maintain a fixed opening over a wide range of engine operation but to reduce the bypass opening for increased scavenging air flow during starting and acceleration conditions.
3 more elements
Dependencies are inferred from the claim text.